To turn two single sleeping mats into one, double-wide mat with no gap between,

Universal Mat Coupler is the right tool. It includes two coupler units, one to be attached right about where shoulders contact the mats and the other at knee distance from the end. Two Velcro-adjustable loops per unit, one for each mat, easily accommodate a variety of mat thicknesses, all the way up to EXPED’s single MegaMats (Note: does not fit duo sleeping mats). In the center, between the two mat loops, an adjustable length of spacer tape ensures that the mats never drift apart, creating a gap. This is gap-free sleeping, folks!

Specifications

Total weight: 1.8 ounces.

Fits all single mats

Kit includes 2 coupler loops