I'm wondering the same, I quickly measured it... but I didn't want to take off the accordian hose I had stretched/forced on it and it looks like 3"... Although it could be slightly bigger... I'm actually wondering if I should get a 3" coupler or a 3"-3.25" reducer to go from the LexAFM to my 3" intake pipe... I know it looks I'll need a reducer to go from the intake pipe I have to my sp61gt... Oh and I was looking at outer diameter..
