Disclosed is a prosthetic elastomeric liner, which can be used without lanyards or straps, in which, upon ambulation, perspiration is voided simultaneously with the reestablishment of a vacuum-aided seal without a vacuum pump. The liner's distal tip comprises a buttress anchored sweat port containing a one way valve continuous with a channel passing through the buttress and liner from its inner surface to its outer surface. The sweat port is connected, optionally integrally, to a prosthetic pin which is inserted into a prosthetic limb.