The Sea to Summit Comfort Light Self-Inflating Mattress series aims to hit that sweet spot of minimal weight and packed size but also provides a comfortable night's sleep. At 5 cm thickness, this mattress is going to protect you from just about any less-than-perfectly flat terrain.  Delta Core Technology Sea to Summit's Delta Core technology makes sure that the additional thickness doesn't equate to an increase in weight and provides even insulation across the length of the mattress. The Comfort Light series is made from lightweight 30 Denier polyester with extrusion laminated TPU, which significantly reduces the risk of delamination. This coring technique has the additional benefit of keeping the top and bottom surface of the PU foam completely intact.  This ensures consistent warmth along the full length of the mattress, avoiding the vertical holes or frame-like gaps that have traditionally allowed warmth to leach downwards.  The full-foam surface also provides significantly improved bonding of the foam to the shell fabrics of the mattress, thereby greatly reducing the chance of delamination. The shape and size of the Delta Cores are adjusted across the different thicknesses of the Sea to Summit Self Inflating Mattress range to ensure strength and durability, while still providing excellent support and self-inflating performance.   Easy to Use and Helpful Multi-Function Valve Sea to Summit have solved the problem of how to pack up a self inflating mattress that tries to re-inflate while you pack it away. A special reversible one-way inflation valve prevents the mat from drawing air back in while being rolled up.  The patent-pending valve has the same slim profile but faster inflation than traditional screw valves, and offers easy pressure fine-tuning and a super-fast deflation rate. Features and Specifications Utilizes Delta Core technology, which keeps body contact areas warmer while still offering great support and pack-ability. Anti-slip print on top and base of mat helps hold your mat in place when camping on sloping ground. Multi-function, patent-pending valve twists over to allow the mat to be rolled tightly without fighting re-inflation as you go. Click here to learn about the Multi-Function Valve At 2 inches thick and an equivalent R-Value of 2.7, the Comfort Light Mat is ideal for comfort-oriented three-season campers. Luxurious 30 Denier knitted polyester fabric is soft and warm to the touch. R-Value: 2.7 Thickness: 5 cm Small: 170 x 51 cm; 595 grams Regular: 183 x 51 cm; 650 grams Large: 198 x 64 cm; 880 grams Sea to Summit Comfort Light Self-Inflating Sleeping Mat / Pad