Alright, here's a little short video on the arrow on the top of a piston. Some folks say that it goes towards the intake. Some folks say that it goes towards the exhaust. Here I have a PK80 and as you can see the arrow is pointing towards the intake. Here is a skyhawk cylinder and it has an arrow on it and it is pointing towards the exhaust. A good way to tell is to always look at your piston. Right there where the keepers are there's two little pins. You want those pins on the intake side, not the exhaust. So you can see this arrow here pointing towards the exhaust has the pins on the back. This piston here for the PK80 is pointing towards the intake. And the pins on it are on the arrow side. The pin always goes towards the intake, not the exhaust. So a lot of times you just need to disregard the arrow. You all have a great day.