PDI Palsonite Cylinder for the TM AEP platform. 

Designed to fit the TM AEP G18C, M9A1, M93R, Hi-Capa, USP and clones.
These Steel Cylinders are non-ported to maximuse the available air volume and Palsonite coated to give extreme smoothness and durability. 
They should be lubricated with a couple of drops of liquid silicon oil.
 
The beveled edge should face towards the cylinder head.