Mini Size Warmers last up to 8 hours and are packaged as pairs. Large warmers: Last up to 24 hours each and are packaged as single units. 3110 packed 30 each. Glove size: Last up to 12 hours each and are packaged as single units. Foot warmers: Pop a pair of these heat generating footbeds into your boots or shoes and you will be walking on warm air for hours. Heated insole: Last up to 6 hours, no trimming, air activated. One pair. 40 Pack.Heat Factory