This is the same cooling pack supplied with the IceVest (Part No. 2750) and the IceCollar (Part No. 2760). Each pack is a mesh container that has three separate pouches (each divided into three sections) filled with a special non-toxic liquid that stays frozen longer than water. Just freeze the pack in a freezer, then enjoy the cooling effect. Cools up to 45 minutes without dripping cold water down your back.