Sleeping Pads Camping & Hiking, Outdoor Recreation, Sleeping Bags & Camp Bedding, Sports & Outdoors, Therm a Rest Therm-a-Rest Luxury Down Camping Mattress Coupler Review by BlackPelican June 18, 2018 No Comments Joins 2, 76 cm wide mattresses Luxurious down sleep surface Increased warmth Snaps to our blankets and comforters Luxurious down sleep surface joins two 76 cm wide mattresses, increases warmth and snaps to our blankets and comforters.