This is a pair of (2) Patented VRP ‘XV4’ Pistons –  

20H Front Pistons.
These are drilled 3h1.4, 1h1.5, 16h.6mm.  The return Holes are 1.1mm. They are lasered with a “F” on them for ‘FRONT’ pistons. 

And

20H Rear Pistons.
These are drilled 3h1.5, 1h1.6, 16h.7mm.  The return Holes are 1.2mm. They are lasered with a “R” on them for ‘REAR’ pistons.

***The pistons are precision drilled on the CnC. Hand drilling this hole pattern does not have the same results. The small holes HAVE to be clean with NO burr, and they have to be straight. Thats impossible to do by hand. So I highly suggest buying the pistons direct from us.

*Important: The VRP ‘XV4’ Pistons are designed to have a washer under and over them. It is important to run washers and that they are correctly installed. Each set of pistons is supplied with a Washer Hardware Pack to make sure you have what you need to install them.

***Note for TEKNO racers:  You can drill the Front Pistons, Large Holes all to 1.5mm and it will allow lower oils in the front that will match the rear oils better.

Each set of pistons comes with 4 different upper washers that are color coded. The washers are made to more or less cover the rubber valves to give different rebound rates. The Black washer gives the most rebound, Red is a little less rebound, Gold is slightly less rebound than the Red washer, and the Blue washer is the least rebound. For tracks that are loose and low grip, or very blown out with large ruts, more rebound is better. On smooth or tracks that have very high grip, less rebound is better. We suggest starting with the Black Washer in the rear pistons, and the Red Washer in the front pistons.

Additional information
Mugen and X-ray - same piston
Tekno and AE - same piston
Sworkz and Sparko - same piston