Why 640gsm changes everything

The number on the tin

GSM — grams per square metre — is how fleece weight is measured. Most wearable blankets on the high street sit between 180 and 260gsm. That's a jumper, not a blanket.

What 640gsm feels like

The Cocoon's dual-layer construction traps a pocket of still air between the outer teddy fleece and the inner sherpa. Still air is what keeps you warm — 640gsm simply means more of it, held in place longer.

• 240gsm — a light hoodie. Fine for autumn.
• 480gsm — a decent throw. Fine on the sofa.
• 640gsm — a cocoon. Central heating optional.

And it still breathes

The two-way zip means you can vent from the top or the bottom, so 640gsm never means stewing. Warmth you can tune is warmth you'll actually use — on the recliner, at the desk, or out in the garden on a cold morning.