1010-S IS A 1.00" X 1.00" FRACTIONAL 10 SERIES SQUARE T-SLOT PROFILE WITH FOUR OPEN T-SLOTS, ONE ON EACH 1.00€ FACE. THE PROFILE IS SMOOTH, WHICH MAKES IT RESISTANT TO DIRT AND DEBRIS BUILDUP WHILE ALSO BEING EASY TO CLEAN. THE 1010-S PROFILE IS COMPATIBLE WITH ALL 10 SERIES FASTENERS. THE FOUR OPEN T-SLOTS ENABLE ACCESS FROM ANY DIRECTION AND ARE USEFUL FOR MOUNTING ACCESSORIES