WinTech Red shoes have a stiffer sole than the WinTech Black Shoes to aid the transfer of power through the stroke.
WinTech shoes are fastened to the shoe plate with M6 machine screws.
NB: Most other manufacturers use M5 screws. Therefore, if you order these shoes for boats manufactured by others, you may have to enlarge your shoe plate holes slightly to accommodate the M6 screws. And, of course, you will want to order a set of M6 flat head machine screws.