I hate those rails. Made 3 myself. shitty. If i ever make another one, its from steel beam welded together. Pvc breaks, is inconsistent and sucks for sliding. Where you screw it to the wood you have a hole, place your board could get stuck. And its easy to break is you land sideways or a little harder then you should. Its funner to make a box because you can use that udhp? i think its called as plastic for the top.... They use it for park boxes.
I didn't drill through the PVC from the top so there are no holes to get tripped up on first of all and I didn't have the time or tools to build a box. All in all it's a 10 foot rail that ur on for all of a second I don't see how sliding is an issue. I already know its not the best but 35 dollars u show me a rail that beats it.