I am replacing all of the rollers on my Fast Load trailer with Stolz poly units. I found what I needed on amazon, and procrastinated a few days. Called the few boat dealers local to Sebring area. It turns out that Lake Placid Marine has an entire aisle dedicated to trailer rollers! Got the RP-7 for $18, 5 LESS than online, and no shipping charge! Going back for the 12's and an ultimate bow stop.