I had ordered a G&P white piston, which GI was reliable as usual and told me it was on backorder, so I got this since it was the same price and very alike. It is very light, and has 4 metal teeth. I had installed this into my JG m16a4 that I use as a DMR. The setup is JG steel gears, G&G upgraded reinforced piston, 9.6v 2000 mah nunchuck, JG high torque motor, (not the new one that is equal or better than the magnum) and the stock m130 spring. This is putting out around 440-450 fps with 15 rps, and after 10k shots, I opened it up to put in a new wireset, and guess what? This piston had no sign that it had been used other than the grease on it and the third tooth removed for angle of engagement. (the second one is already gone, as it shows in the pic) This is a very nice piston for speed and moderate power upgrades, since it is light and very durable.
Do yourself a favor and buy one!
-4 metal teeth (good if you want to short stroke up to 3 teeth)
-outstanding quality for $25
-none, I have not found anything that I don't like about this piston