Cylinder Heads seal your Cylinder and transfer the air to the hop up chamber.
Some upgrade cylinder heads have extra O-rings for minimal airloss.
Cylinder and Cylinder heads come in different types.
If you have a Silent pistonhead, you must check if your cylinderhead is shaped to accept this.
A Bore Up Cylinder Head must be combined with a Bore Up Pistonhead, Bore Up Cylinder and Bore Up Airnozzle.
Cylinders come in different types. The Cylinders are responsible for the aircapacity of the gearbox, and different types are calibrated for different barrel sizes.
Please note! Bore Up is only usefull with barrels above 580mm!