Fits a 1/2 pvc pipe. I used it to put support across the inside middle top of a pvc box frame. The longer pipe hole goes all the way through, you can pass one solid piece of pipe through he one hole. In the picture the tube facing down is slightly looser then the others, didnt want to re-edit again. With downward pressure it wont really matter, its not really all that loser either way. You can find my 3 way fitting that meets this connector on the bottom in my profile also.

Post pics if you can of any builds you make of this.