Purpose

• Inflatable mattresses are on the extreme luxury end of camping pads, so much so that they're hardly recognizable as a sleeping pad at all--although they serve the same basic purpose. The right sleeping pad will insulate you against heat loss to the ground, but be small and light enough that you can fit it into your packing schema.
  
  

Description

• Self-inflating sleeping pads are thin, person-sized versions of an inflatable mattress. You unroll the pad, open the valve, then walk away and do something else as the pad slowly self-inflates. You can also blow air into the valve to speed the inflation. The other two common types of sleeping pads are open-cell foam, which traps air for extra insulation but also absorbs water like the sponge it resembles, and closed-cell foam, which doesn't absorb water but doesn't trap as much air for extra insulation as open-cell foam pads.
  
  

Size

• Inflatable mattresses aside, sleeping pads typically come in short, regular or long lengths to accommodate campers of varying height. You may also encounter three-quarter or torso-length sleeping pads, designed for ultralight backpackers that are willing to compromise on insulation in order to shave a few ounces and inches off the final pack weight.