A catheter having a fibrous reinforcement is formed by anchoring a filament at a proximal end of a core member, and winding the filament onto the core member continuously from the proximal end to the distal end of the core member and then back to the proximal end to form a first fibrous layer. The method includes inserting a second section of the filter into an aperture defined in the electronic circuit board, such that a first section of the filter is secure against an electronic circuit board first surface and a first lead of the filter extends to a solder pad on the electronic circuit board first surface. There is also provided a catalyst suitable for the vapor phase production of alkylene oxide from olefins and oxygen comprising an alumina-based carrier having a sodium solubilization rate no greater than 5 ppmw5 minutes; and catalytically reactive silver deposited on said carrier. Each switch unit belongs to a number of combinations and any two combinations have at most one switch unit in common.