Forclaz Trekking Silk Bag Liner MT500 Review

Overview

The Forclaz MT500 is a 100% silk, mummy-shaped sleeping bag liner that weighs 110 g and packs to half a liter. It’s built for backpackers who want a cleaner bag and a small warmth bump without paying boutique silk prices. The trade-off is fit: the cut is narrow, and the silk is more workmanlike than luxurious.

Key Specs

Spec	Detail
Weight	110 g (3.9 oz)
Material	100% silk (carry bag: 95% polyester, 5% silk)
Dimensions	220 cm long, 77 cm at the head, 54 cm at the toes
Packed volume	0.5 L
Shape	Mummy
Claimed warmth boost	Approx. 1.5–2°C (3–4°F)
Carry bag	Included
Care	Machine washable

Performance

Weight and packability. At 110 g, the MT500 undercuts Cocoon’s silk mummy liners, which a Canadian reviewer put at 160 g. That’s 50 g saved for a comparable fabric. The liner stuffs into a small attached pouch, and the same reviewer said it ends up so compact that it travels in his bag by default. For thru-hikers counting every ounce, the 3.9 oz figure is the headline. It is a lot less than a fleece liner and not far from a bare-minimum sheet.

Warmth. Decathlon says the liner adds roughly 1.5 to 2°C to a sleeping bag’s rating. That’s a modest number, and it’s the right one to plan around. The liner takes the chill off a bag that is just short of the night’s temperature. It won’t turn a 10°C bag into a 0°C bag. Silk’s real contribution to warmth is cutting the clammy, sticky contact between skin and nylon liner fabric, which makes a cool night feel less miserable. Treat it as a comfort margin, not a replacement for a warmer quilt.

Hygiene. This is where silk earns its place. The liner takes the sweat, sunscreen and trail grime so the bag doesn’t. Decathlon points out that washing a bag less often preserves its loft and durability. The MT500 is machine washable, which makes it far easier to clean after a week of hostel or hut nights than a down bag. Owners also use it alone in huts and cottages, where a clean sheet layer is the point.

Comfort and fit. Reviewers describe the MT500’s silk as slightly coarse by silk standards, nicer than the slippery, noisy nylon of a typical bag, but not the glassy hand of a silk shirt. The mummy cut is the bigger issue. One 6’3” (190 cm) user found the seam high and the footbox narrow enough to make turning over a chore. He eventually cut the seam open and used it as a flat sheet with a small footbox, which he found much more comfortable. Side sleepers and restless sleepers should expect the same tightness. Those who sleep still in a mummy bag will find the shape matches their bag and adds little bulk.

Durability. Silk has a reputation for fragility, but the MT500 has held up better than expected. After close to a year and an estimated 50-plus nights, the fabric looked nearly new, though the stitching started to unravel. That’s a fixable seam problem, not a fabric failure. The same reviewer ranked a Cocoon ripstop silk liner above it and kept the Forclaz as his beater. Pack it away from rough zippers and sharp pad valves and it should last.

Value. Retail pricing varies by market. In the US it has been listed at $40, down from a $59.99 list price. A Canadian reviewer originally paid about $55. Customer ratings are consistently high: 4.5 across nearly 600 reviews on Decathlon’s UK page, and 4.6 to 4.7 across roughly 670 reviews on its Indian and US pages.

Pros & Cons

Pros

• 110 g, 50 g lighter than a Cocoon silk mummy liner
• Packs to 0.5 L with an included pouch
• Machine washable, which keeps a bag’s insulation cleaner for longer
• Silk feels better than bag nylon against bare skin
• Fabric has proven durable over about 50+ nights
• Inexpensive for real silk

Cons

• Narrow mummy cut is restrictive for taller or restless sleepers
• Silk is on the coarse side
• Stitching can unravel with extended use
• Only about 1.5–2°C of added warmth
• No ripstop weave; ranked below Cocoon’s version by one long-term user

Who Should Buy This

Hikers who use a mummy bag, sleep fairly still, and want an inexpensive way to keep the bag clean and gain a couple degrees of comfort. It also suits hut-to-hut and hostel travelers who need a sheet that stuffs into a pocket. Tall side sleepers and anyone who dislikes a snug footbox should look elsewhere, ideally at a rectangular or roomier liner. Cold sleepers needing a real temperature bump should buy a warmer bag or a fleece or thermal liner instead.

Verdict

The MT500 delivers what silk liners are for: a cleaner bag, a smoother feel and a small warmth cushion, all in 110 g. The tight cut and unfinished seams keep it from being flawless. At its price, though, it’s an easy recommendation for mummy-bag users.