HEAT WAVE Instant Reusable Hand Warmers - 1 pair - Premium Quality - Medical Grade - MADE IN USA! (not China) Hand Warmers (3x5 or 3x6) Medium and Large Rectangles (5x9 / 8x12) Large Round (6&#034; diameter circle) Shoulder, Back, and Neck (6x18) Reusable One Click to Heat Boil to Reuse Firmly press large side of stainless steel trigger with finger, or back of a pencil or pen Massage heat pack after pressing trigger until completely crystallized Apply heat pack to desired area after heat pack has completely crystallized for best results Insulate heat pack in a towel or cloth material for longer lasting heat Place heat pack in rapidly boiling water until crystals completely dissolve - about 20-25 minutes - then simmer for 10 Wrap heat pack in cloth to prevent burning in the event that you forget about it Remove heat pack and allow to cool to room temperature before next use If heat pack crystallizes after boiling, re-boil until crystals are completely dissolve Store heat pack in liquid form for best results Store at room temperature Do not store in car for long periods