This longer life platen drive belt can only be installed on 170AX3 units AFTER the upgraded platen pulley and the upgraded intermediate pulley contained in kits 43767M (RH) or 43766M (LH) have been installed. Upgraded pulley kits 43767M & 43766M also include the platen drive belt contained in kit 14196M. This belt can be directly installed on 170PAX4 units with serial numbers greater than or equal to 05C07230006. 170PAX4 units with serial numbers less than 05C07230006 will first need to install the upgraded platen pulley (item 2) and the upgraded intermediate pulley (item 2) contained in kits 43767M (RH) or 43766M (LH) BEFORE installing the platen drive belt contained in kit 14196M. Upgraded pulley kits 43767M & 43766M also include the platen drive belt contained in kit 14196M.