The JACKSON SAFETY 225 plus winter liner gives a bit of extra warmth for cold weather environments coded for a temperature range of 32 to 0 deg F or 0 to 20 deg C It is designed to be easily worn under caps and hats including hardhats and features a hook and loop fastener for a comfortable, close fit The outer shell is made of quilted nylon with extrathick foam fill and the inner lining is a soft polyester fleece It meets 16 CFR 1610, Class 1, so you can confidently use it to protect you against the cold elements