Abstract: One embodiment includes a bicycle frame that includes a plurality of square cross-section tubing members, wherein all tubing members are straight, and are consistent in cross-sectional dimensions along their length and wherein each tubing member is cut to length with a straight cut defining a tubing opening formed by an edge that extends along a single plane.

Abstract: One embodiment includes a bicycle frame that includes a plurality of square cross-section tubing members, wherein all tubing members are straight, and are consistent in cross-sectional dimensions along their length and wherein each tubing member is cut to length with a straight cut defining a tubing opening formed by an edge that extends along a single plane.

Abstract: A particulate filter particularly suited for analytical gravimetric weighing applications is disclosed. The particulate filter includes a polytetrafluoroethylene (PTFE) media supported by a ring and yields stable microgram and submicrogram weighing results. The support ring may be PTFE, metal foil, or another non-hygroscopic polymer such that the mass of the filter does not vary with changes in atmospheric moisture. The filter simplifies the discharge of electrostatic charge buildup such that when a conductive filter media is combined with a conductive ring device, the discharge may be accomplished by placing the filter on a grounded weighing pan or other surface. The particulate filter can simplify filter identification by including identification symbols imprinted on each side of the filter media.