Dr.Ho's Magic Heat Pad 2 pack Venture heating pads ItemNo Size Material Donning Colour DROPSAFE SAFETY PEN NEEDLE 31G X 8MM ItemNo Size Material Donning Colour Measurements Thickness 956 XSmall Nitrile PF Dark Blue 230 mm x 70 mm 4 mil 966 Small Nitrile PF Dark Blue 230 mm x 80 mm 4 mil 976 Medium Nitrile PF Dark Blue 230 mm x 95 mm 4 mil 986 Large Nitrile PF Dark Blue 230 mm x 110 mm 4 mil 996 XLarge Nitrile PF Dark Blue 230 mm x 120 mm 4 mil Square Pulse Pulse Amplitude 0 100 mA peak to peak (into 500 ohm load) Pulse Rate Width 2 150 Hz 50 300 µS Contraction Relaxation 2 90 seconds (Adjustable) Power Source 9 Volt Battery Warranty 1 Year Manufacturer Warranty Ho Magic Heat Pad 2 pack All you have to do is bend or click the coin inside the solution and it will react with the liquid to create soothing therapuetic heat