Profile: Thompson Lightning Protection, Inc. provides adapters, fasteners, ground guards, splicers, wedges and nails & screws. Our fasteners include round head machine screws, cap screws, washers and hex nuts. The No.242XP downlead guard is an 8'0" guard for protection of exposed down conductors. It can be mounted to wood, metal or masonry surfaces. The No.125 bimetal clamp is a standard forged pure copper cross run clamp for all standard cables.