The Series 25 Spindle Adaptor Kit is required when Internal Spindle, 8" (799-0028), Internal Spindle, 16" (799-0029) or External Spindle, 8" (807-0016) are used with Series 25 tool post grinders.
The kit includes 4 Pulleys (671-0156, 671-0157 (2) & 671-0158) and 3 Belts (R429-0056, R429-0057 & R429-0058).