This mulch kit is designed for use with Stiga, Mountfield, ATCO, Alpina, Castel Garden and other Stiga/GGP 92cm rear collection ride on mowers with the model prefix NJ92. This mulch kit can enable you to convert your collector tractor into a mulching tractor. Mulching chops the grass into small pieces and forces those clippings into the ground. The small finely clipped grass pieces then decompose quickly and help fertilize your lawn in a natural way rather than using chemicals.