IMSA Helmet Plug and Switchcraft jack for all standard 3.5mm ear plugs. Stainless mounting hardware included. This racing helmet kits feature a straight coiled cord easy to use, prewired mount system. Durable polyurethane insulation provides strength, flexibility and resistance to abrasion while spiral shielding provides superior protection [3M shrink wrapped] against radio frequency RF and electro-magnetic EM interference. INCLUDES STAINLESS STEEL MOUNTING HARDWARE