Set of 4 on the Ridgid storage box. 2-hole match. Had to drill 2. Easy to drill holes with the right bit. These bikes are rated at 250 pounds each, and with all four, I'm not afraid the crate will be too heavy for them. I used 3/8 connectors for assembly. The wheels roll super easy. The wheel locks are easy to engage and disengage. Mine is for home use as the garage is a gym. The box rolls in and out easily on the stable mat and lowers onto the concrete. If I have a second smaller box I will buy it again. And I chose them over the Home Depot equivalent. Black looks way better and I saved $10.