Abstract: A Robertson driver is disclosed which has a slot (10) in the end of the tip (12) that can fit over a wire, enabling the user to manipulate the wire.

Abstract: An improved exhaust system (24) uses the entire length of the system in which to perform the essential functions of muffling noise and converting unburned hydrocarbons. The improved exhaust system (24) performs these functions with a relatively uniform minimum diameter along its length. The exhaust system (24) includes a uniform outer diameter pipe (26) and elements (44) of porous material (46) forming a plurality of filters (50) through which the exhaust gas flows and which attenuates sonic frequency sound waves in the exhaust. The elements (44) are preferably elongate strips which may be folded into rectangular filters (60) or elliptical filters (90). The rectangular filters can be folded sufficiently to form squares and the elliptical filters to form circles. The rectangular filters define passageways (62-68) between the edges of the filters and inner wall (70) of the pipe (26) which further attenuates exhaust noise through imbalances in the gas flow.