These sets include discs and handles for custom seal driver assembly to provide a pilot (to prevent cocking), a spacer (so force is applied on the proper area) and a driver (for even force dist.). Discs range from 1/2 in thru 4 1/2 in diameters in 1/16 in increments. Each set includes a handy plastic box with pre-cut tool tray. Power Team® 27797 Master Set, 1/2 in to 4-1/2 in dia, 65 Discs