Compatible with the Malone 3 or 6 kayak free standing racks. Two Kits are recommended for the 6 kayak rack. The Malone Free Standing Rack Caster Wheel Kit lets you roll your Malone Free Standing Rack around in the garage with ease. This kit includes 4 rolling caster wheels with push-down wheel locks. A 550lb weight capacity, this kit can make moving your loaded 3 or 6 Kayak FS Kayak Rack very simple. The Malone FS Rack Caster Wheel Kit is easy to install with just nuts and washers.