The merino wool with felt liner (white on the bottom and black on top) has 3/8" felt inside. This liner is about 5/8" thick in total.
The double sided merino wool liner (white on top and bottom) is our 100% merino wool on both sides with no extra padding inside. This liner is about 1/4" thick when compressed. It can be hosed off or washed in a washing machine on gentle with soap appropriate for wool on a cool temperature. Air dry.