Made by Kahtoola, is their winter snow Flight boot. The FLIGHTboot is a 3 millimeter neoprene insulated overboot designed to be worn over trail running shoes to conserve weight and to be used for winter snow trail running, walking, hiking or camping in the snow. If they are sized properly, there is enough room inside for a lightweight insulated boot or trail runners plus a neoprene bootie. Or you can wear with a good pair of arch supporting orthotics and good socks to fit size 8 mens or 10 womens. The boot can also be worn with Kahtoola's Flightdeck step in snow shoe, to provide flotation for hiking on fresh snow. Boots are brand new, size xtra small - unisex, size 5 men's or 7 women's. $59 obo.