Reiff · Winter Wearable Blanket with Sleeves
Organic Merino Wool Sleep Sack for Cold Nights
German-made wearable blanket with sleeves, organic merino wool exterior and cotton sherpa lining. 3.5 TOG rating for temperatures below 64°F. Sizes 3 months–4 years.
About the Maker
Reiff is a fully-processing flat knitting company founded in 1939 by Adolf Reiff in Gömmingen, Germany. Unlike brands that source finished fabrics, Reiff knits, finishes, and dyes everything in-house or within a 50 km radius of their facilities—giving them complete control over fiber quality and environmental practices. The company pioneered washable organic wool nappies in the 1970s, pioneering ecological textiles decades before it became mainstream. Today, Reiff produces exclusively organic textiles, holding GOTS and kbT certifications and sourcing Patagonian merino wool from farms certified under kbT (kontrolliert biologische Tierhaltung) standards.
When to Wear
Winter Sleep Sack for Cold Nights
This wearable blanket with sleeves is designed for winter sleeping when room temperatures fall below 64°F (18°C). The sleeves keep your baby's arms warm without the bulk of extra layering, and the full-length side zipper makes diaper changes seamless—no need to remove the entire blanket. Unlike loose crib blankets, this sleep sack eliminates suffocation risk by keeping your baby covered safely while they move.
This is not a transitional-season piece. For rooms warmer than 64°F or for layering in milder months, reach for a lighter-weight sleep sack or base layer instead. The 3.5 TOG rating is intended for sustained cold, not for rooms where temperatures fluctuate.
Materials & Construction
Fiber Breakdown
Exterior
100% organic merino wool, knitted and lightly fulled for durability and natural water resistance
Lining
100% organic cotton sherpa for softness and breathability against skin
Certifications
GOTS (organic fiber), kbT (organic livestock welfare), made entirely in Germany
Why This Combination
Merino wool naturally regulates temperature and resists odor; cotton sherpa is soft, breathable, and easy to care for compared to wool on skin
What "GOTS certified" means: Global Organic Textile Standard is the leading worldwide standard for organic textiles. It covers fiber farming, processing, dyeing, finishing, and chemical use. Reiff's commitment to GOTS means no synthetic dyes or harmful chemical treatments.
What "kbT" means: Kontrolliert biologische Tierhaltung (controlled organic livestock farming) certifies that the Patagonian merino sheep are raised on certified organic pastures with strict animal welfare standards and no mulesing.
Temperature Guide
3.5 TOG Rating for Cold Nights
TOG (thermal overall grade) measures warmth. This wearable blanket is rated 3.5 TOG—the warmest rating in the typical sleep sack range. It's suitable for sustained cold-weather sleeping.
Room Temperature
Below 64°F
18°C and colder. This is where the 3.5 TOG blanket performs best. Layer with a long-sleeve bodysuit underneath if needed.
Approximate TOG
3.5
Warmest rating; equivalent to heavy quilted sleep sacks. Designed for winter months in cold climates.
How to use this guide: If your bedroom averages 55–64°F during winter, this sleep sack will keep your baby warm. If your room stays warmer than 64°F even in winter, or if you live in a mild climate, consider a lighter-weight option. Your baby should never be too warm—overheating is also a concern. If you're unsure, use your hand: you should be able to feel mild warmth on your baby's chest through the cotton lining, not heat.
Key Features
What Makes This Sleep Sack Work
Sleeves for Arm Warmth
Unlike armhole-only sleep sacks, sleeves keep arms covered and warm without adding weight. Arms move freely within the sleeves.
Full-Length Side Zipper
Diaper changes don't require removing the entire sleep sack. Zipper runs the full length for complete access while baby stays covered and warm.
Temperature Regulation
Organic merino wool naturally regulates temperature and resists odor. Cotton lining is breathable and wicks moisture away from skin.
Lightweight for Its Warmth
Merino wool is dense but not heavy. This sleep sack provides significant warmth without bulk, ideal for active sleepers and tossers.
Sizing & Fit
Find Your Size
Reiff sizing is based on age and height. Measure your baby from shoulder to toe for the most accurate fit. European sizing runs slightly slim—if your child is at the upper end of an age range or tall for their age, consider sizing up.
| EU Size |
Age Range |
Height |
Sleeve Length (approx.) |
Total Length (approx.) |
| 62–68 |
3–6 months |
24–27 inches (61–68 cm) |
7 inches |
25 inches |
| 74–80 |
6–12 months |
29–31 inches (74–80 cm) |
8 inches |
30 inches |
| 86–92 |
1–2 years |
34–36 inches (86–92 cm) |
9 inches |
35 inches |
| 98–104 |
2–3 years |
38–41 inches (98–104 cm) |
10 inches |
40 inches |
| 116 |
3–4 years |
45 inches (116 cm) |
11 inches |
45 inches |
Sizing Note
Check product measurements before ordering. Age suggestions are approximate and may vary by individual child. A sleep sack that is too large allows baby to move inside it; too small restricts movement and comfort.
Be Honest
What to Know Before You Buy
Best For
Parents in cold climates or those with consistently cool bedrooms (below 64°F) who want a winter sleep sack that stays on through the night. The sleeves and full-length zipper make this especially practical for active toddlers who move around during sleep. If your baby has never worn wool, the wool/cotton combination is gentler than 100% wool next to skin.
Trade-Offs
This is a heavy sleep sack. It won't transition between seasons—you'll need lighter options for warmer months. Merino wool requires cold-water washing and lay-flat drying; it cannot go in the dryer. A small percentage of people report wool sensitivity, though the combination of merino (fine micron count) and cotton lining makes reactions less likely than with coarse wool. If your child has reacted to wool before, start with a wool/silk blend or pure cotton sleep sack first.
Investment & Durability
This is premium pricing for a reason. Reiff's German manufacturing, complete control over fiber sourcing, and organic certifications all cost more than offshore production. With proper care, this sleep sack will last through multiple children and hold up to weekly washing. The full-length zipper is durable and reliable. If you have multiple children, this pays for itself over time.
Care & Washing
Keep Your Sleep Sack Beautiful
Cold water only Wool wash detergent Lay flat to dry No tumble dry Do not bleach
How to wash: Hand wash in cold water using a gentle wool detergent (Eucalan, Sonett, or similar), or use the wool/delicate cycle on your machine with cold water only. Fill the machine half to three-quarter full, add detergent, place the sleep sack inside, then add water. Avoid soaking or agitating. Press water out gently—never wring. Reshape while damp and lay flat on a clean towel to air dry, away from direct heat and sunlight.
Why cold water matters: Hot water causes wool fibers to swell and felt together, permanently shrinking and thickening the fabric. Once felted, it cannot be undone. Cold water preserves the fiber structure and softness.
How often to wash: Wool naturally resists odor and bacteria. Most parents wash wool sleep sacks every 2–3 weeks, or whenever visibly soiled. Airing between uses (hang outside or drape over a chair) extends the time between washes and refreshes the fabric naturally.
Pilling: Merino wool can pill slightly with friction. If pilling occurs, gently remove pills with a soft brush or fabric shaver. This does not affect the integrity or warmth of the sleep sack.
Questions
Frequently Asked
Will my baby overheat in this sleep sack?
Not if you match it to your room temperature. The 3.5 TOG rating is designed for sustained cold (below 64°F). If your bedroom averages warmer than this, even in winter, choose a lighter sleep sack. Never use this blanket in a room above 72°F. You should feel mild warmth, not heat, on your baby's chest through the lining.
Is this good for babies with sensitive skin?
Possibly. The organic cotton lining sits against skin, so your baby isn't in direct contact with wool. Fine merino at approximately 20 microns is soft and rarely causes irritation in babies without a pre-existing wool sensitivity. If your child has reacted to wool, start with a wool/silk blend instead, which is gentler. GOTS certification means no synthetic dyes or harsh chemicals.
Can I use this sleep sack if I also use a swaddle or wearable wrap?
No. Sleep sacks are designed as a standalone sleep solution, not to be layered under or over other heavy blankets or wraps. Using multiple layers risks overheating. Choose one sleep system and stick with it.
How long will this sleep sack last if cared for properly?
With proper cold-water washing and lay-flat drying, this sleep sack can last 5+ years of regular use, or through multiple children. The zipper is robust and designed for durability. Many parents pass Reiff pieces between siblings and friends.
What's the difference between this and a regular blanket?
A wearable blanket (sleep sack) stays on your baby as they sleep, moving with them. Loose blankets can cover a baby's face or be kicked off, creating suffocation or temperature risks. Sleep sacks are the current recommended safe sleep practice by pediatricians and organizations like the American Academy of Pediatrics.
What should I layer underneath this sleep sack?
In cold rooms, layer with a long-sleeve organic cotton or merino bodysuit underneath, depending on your baby's sensitivity. If your baby wears a diaper, that's usually enough underneath the sleep sack. Avoid adding heavy pajamas on top of the sleep sack—the 3.5 TOG rating accounts for standard bedroom clothing, not multiple layers.
How is this different from Disana or Engel sleep sacks?
All three are German heritage brands with GOTS and kbT certifications, but each has a different focus. Reiff specializes in flat-knit merino and boasts complete control from knitting to finishing in-house. The sleeves on this model are unique to Reiff's winter design. Disana is known for boiled wool outerwear and heavier sleep sacks; Engel focuses on finer merino for base layers and lighter sleepwear. Choose based on your room temperature and preferred weight.
