Product review (2 stars): Be careful inserting the keepers into the wheels
Wheels have a nylon "keeper" that must be inserted into the wheel first, then keeper and wheel can be slid onto the rack. But the nylon is so stiff, it broke on one keeper before I could squeeze it into the wheel. Good thing I bought the four pack when I only needed one. Now I have two spares and an extra wheel that is useless without the keeper. Reasonable price to get the job done.