Abstract: An adjustable hair piece construction includes a filamentary support element formed into a loop so as to fit around the head of a wearer. Hair is affixed to the loop element so as to, in use, hang down therefrom. An adjustment assembly for adjusting the size of the loop includes an abutment member including first a second bores therethrough. Portions of the support element extend through each of the bores so that the abutment member is movable on the support element between stops at the ends of the latter. A releasable diameter fixing member is movable along the support element between fixed positions. In such a fixed position, and with one end of the abutment member in engagement with one of the stops, the fixing member engages the other end of abutment member so as to fix the position of the abutment member and thus fix the size of the loop.