Rotary Corp brand aftermarket product. Front Caster Wheel Assembly Fits Ferris 5101418. Pneumatic 11x4.00x5 caster wheel assembly, smooth tread, 4 ply, Silver. Fits models F50XT 36" cut, F800X 61" cut, IS500Z 44", 52", 61" cut and IS600Z 44" and 48" cut.