Abstract: A back rest assembly includes a base assembly mountable adjacent a resting surface and a back rest having a supported side pivotably supported by the base assembly and an unsupported side spaced laterally apart from the supported side along a lateral axis. When the base assembly is mounted, the back rest is positionable over the resting surface and selectively pivotable about the lateral axis for adjusting an angular position of the back rest relative to the resting surface.

Abstract: A wheeled device for enabling a scuba tank or the like to be moved overground, instead of the user having to carry it, this device having an elongate axle, adjacent each end of which a wheel is rotatably amounted. A pair of tank-engaging members are utilized in connection with the axle, such members being movable between a nested position, in which the members require minimum storage space, and a position in which the members are separated to a limited extent. One of the members has a support platform for supporting a scuba tank, and each of the members has a sidewall-engaging portion for engaging the sidewall of a scuba tank inserted between the sidewall-engaging portions, to rest upon the support platform. Thus, when the scuba tank is resting on the support platform of the one member, the sidewall-engaging portions of both members tightly grasp the sidewalls of the scuba tank, such that the wheeled device does not drop off should the user lift only the scuba tank.