Dreamruns Direct Connect Ski & Snowboard Helmet Audio Kit Basic ski and snowboard helmet speakers produce awesome sound at an even more awesome price. Full fidelity speakers 20Hz to 20kHz makes these great for everything from Rock to Rap to EDM. Fit in all ski and snowboard helmets with helmet pockets (almost any decent helmet has either a zipper or velcro on the liner for installation) 40mm drivers what else more do you want. (1.57 inches)