HHIP 2-1/2" x 3/4 Bore 45 Degree SE42 Index able face mill with 4 Teeth and 45 degree lead angle allows an increase of feed rate by 50% over 90 degree face mill and also allows this face mill to used on smaller horse power mills. It accepts industry standard SEAN / SEKN / SEKR 42 insert which has a positive 20 degree clearance angle. It accepts industry standard SEAN / SEKN / SEKR 42 inserts which have a positive 20 degree clearance angle. The insert pockets are designed to be 19 degree positive inclined to minimize vibration and allow fast cutting while lowering cutting noise. Inserts are NOT included. Overall height is 1.89". D1 is 3.01". ap is 15/64". Shim size is SEAD42AD.