Abstract: Lighting apparatus for high pressure underwater use are disclosed. In one embodiment the lighting apparatus comprises a housing for withstanding ambient exterior pressure at a depth of approximately 500 feet or more, a transparent pressure bearing window positioned at a forward end of the housing, and a multilayered stack for bearing substantially all of the loading applied to the transparent pressure bearing window at a depth of approximately 500 feet or more disposed in the housing behind the transparent pressure bearing window is disclosed.

Abstract: Structure associated with the seat of a wheeled vehicle, such as a bicycle, provides adjustability of the seat about a horizontal axis transverse the longitudinal axis of the vehicle, and provides adjustment of the seat in a horizontal plane parallel the longitudinal axis of the vehicle. The structure generally includes first and second seat post members which are articulable about an axle pin, an interlocking element engageable with a locking element to provide selective adjustment of the seat post members relative to each other and a housing surrounding the mechanism. Horizontal adjustment structure generally includes a slidable arm positioned within a bracket, and the bracket is attached to one of the seat post members. The rotational and horizontal adjustments provided by the structure of the invention can be accomplished in a matter of seconds while the rider is seated on the vehicle.