Nice vintage Alpine Designs of Boulder Colorado down filled camp slippers. These men’s size large booties are comprised of a nylon upper and lining, thick Cordura base and bottom with a simi-rigid foot bed. Inside is a ring of elastic around the mid ankle to keep them from slouching. There is a full, tie-able drawstring around the top of the ankle. The down is still full and pillowy making for some very warm, very comfortable slippers.
Measurements (outside)
heel to toe: 12.5 inches
width across ball of foot: 4.5 inches
Basecamp Vintage & Archives 
I have a pair of purple and orange ones I bought in 1975 with a A-frame tent. Boots are warm to this day, tent was stolen sadly