The SCR-44 is specifically designed for smaller compact tractors and roll-bar-equiped zero turn mowers. Fits all roll bars 2"x2" up to 2"x3"	The XLR-52 is specifically designed for larger compact tractors and mid size utility tractors with 2"x2" up to 2"x3" roll bars.	The SXL-64 is specifically designed for larger tractors with up to 3.5"x5.5" roll bars.