Model Part Number Backhead Thread
MR132 Hammer 4 1/2" Remet MR132AS01 4 1/2" Remet
MR132 Hammer 4 1/2" Remet - Low Air MR132AL01 4 1/2" Remet
MR132 Hammer 4 1/2" Metzke MR132AS02 4 1/2" Metzke
MR132 Hammer 4 ½" Metzke - Low Air MR132AL02 4 1/2" Metzke