The RBG 712-50 kit converts a RBG 712 grinder to a RBG 750 grinder. The kit allows the user to add a second grinding wheel with a flap grinder disc to the RGB 712 for sharpening mulching blades and other curve surface blades. The additional flap wheel grinder wheel is a versatile add on to your RGB 712. Easy to install and easy to remove. RBG Mulching Adapter kits are available for all traditional model RBG Grinders.