Corinthia Grizzly Sleeping Bag Liner Review: Warmth, Fit, and Value

Introduction

The Corinthia Grizzly is a mid-weight fleece sleeping bag liner designed to sit inside an existing sleeping bag, under a blanket, or on its own when the weather allows. It uses a mummy cut, carries a long zipper along the left side, and packs into a small stuff sack with a handle and a drawcord at the top.

Corinthia makes a broad range of tactical and outdoor equipment, and its products can be harder to find in some markets than others. The Grizzly sits at the warmer end of the brand’s liner range, and that positioning matters when you are deciding how it fits into the rest of your sleep kit.

In use, the liner is a simple piece of gear with a narrow job. It adds warmth, it protects the inside of a bag, and it gives you a lighter option for mild nights when a full sleeping bag is more insulation than you need. The interesting questions are how much warmth it actually contributes, how small it packs, and whether the single available size will work for you.

The measurements below come from hands-on use across a wide temperature spread, from warm summer nights through to the shoulder season, so they reflect how the liner behaves in practice rather than how it reads on paper.

Who This Sleeping Bag Liner Is For

This liner is aimed at campers who want to extend the useful range of a sleep system without buying a second bag. If your current setup leaves you cold in the shoulder months, a liner is one of the least expensive ways to add insulation, and it keeps working when you change bags later.

It also suits anyone building a light, low-cost kit. Because the liner can be used alone, with a thin down blanket, with a poncho liner, or inside a sleeping bag, one purchase covers several scenarios instead of one.

The mummy cut is worth checking carefully. The liner measures roughly 88.5 inches long, about 35 inches wide at the top, and tapers to roughly 23 inches. Those figures are approximate because the fleece is stretchy, so it gives in both directions when you move. If you are close to the upper end of those dimensions, plan around the taper at the foot end rather than the widest point.

Warmth and Real World Comfort

The core claim for this liner is warmth, and it holds up. The fleece construction adds roughly nine degrees to a sleep system, which is enough to change how a given bag performs on a cold night.

Testing has covered nights from roughly 65 degrees down to about 36 degrees, in conditions ranging from calm summer evenings to strong wind. On one trip with temperatures near 48 degrees, the liner paired with a very thin down blanket stayed warm and comfortable despite heavy wind. That is a useful data point because wind is usually what makes a marginal sleep setup feel worse than the thermometer suggests.

Around 50 degrees is the point where the liner on its own starts to feel like not quite enough. Adding a poncho liner on top of it comfortably extends the setup into the 40s. How you experience that threshold will depend on whether you sleep warm or cold, so the sensible approach is to test your exact combination on a short trip before relying on it somewhere remote.

Materials, Fit, and Packed Size

The main material is a mid-weight fleece, and it is the reason the liner feels warm rather than merely adding a layer. The long zipper runs from the foot box all the way to the top on the left side, and it moves smoothly. That full-length opening is more useful than it first appears, because on hot nights you can open the liner out and use it as a blanket instead of a closed bag.

Packed down, the liner measures roughly 6.5 inches by 8 inches and weighs about 1.2 pounds including the storage bag. The stuff sack has a handle for pulling the liner out and a drawcord at the top, but no compression straps, so the packed size is not as tight as it could be. A rubber band or a hook-and-loop strap will bring it down further if you want to save space.

Corinthia offers the liner in olive green and black. The olive version is widely available, while the black version is harder to find.

Durability and Build Quality

Build quality is where this liner quietly earns its place. After roughly 20 uses, the fleece remains in excellent condition with no loose threads, and the stuff sack and drawcord have held up without issue.

That matters more than it sounds. A liner takes constant abrasion from movement during the night and repeated compression in a pack, and a fleece that pills or sheds fibres quickly becomes unpleasant against the skin. So far this one has shown none of that.

Things to Consider Before Buying

The most important limitation is sizing. The Grizzly is available in one size only, so the measurements are not a guide, they are the specification. Check the 88.5 inch length and the 35 inch to 23 inch width taper against your own height and sleeping position before you commit.

The zipper is fixed on the left side and cannot be ordered the other way. If your sleeping bag has a right-side zipper, the two will not line up, which is a minor annoyance rather than a dealbreaker but is worth knowing in advance.

Corinthia also makes a polyester cotton liner that is cheaper, less warm, and closer in feel to a sheet. The Grizzly is the fleece option and the warmer of the two, so pick based on the temperatures you actually camp in rather than the price difference alone. Finally, because the stuff sack has no compression straps, plan on adding your own strap if packed volume is tight.

Buying Advice

At around $68, the liner is fairly priced for a fleece model from a brand that generally sits above budget tier. Sleeping bag liners can get expensive, and this one lands in a reasonable middle ground given the materials and the warmth it delivers.

The value case gets stronger when you treat it as one component of a kit. Pairing the liner with a thin down blanket costs roughly $120 for both pieces, weighs about two pounds together, and comfortably handles temperatures into the 40s. That is a genuinely light and inexpensive sleep system, and it is flexible enough to be reconfigured as conditions change. Availability can be limited in some markets, so it is worth confirming stock before you plan a trip around it.

Conclusion

The Corinthia Grizzly is a warm, comfortable, and well-made fleece liner with a clear purpose. It adds roughly nine degrees to a sleep system, works alone or layered, opens flat as a blanket, packs small, and has held up to repeated use without any wear worth noting.

The trade-offs are straightforward. There is one size, the zipper is on the left only, and the stuff sack could compress further with a strap you supply yourself. If the dimensions suit you and you want a low-cost way to stretch an existing sleep system into colder weather, this is an easy liner to recommend.