Quick Products Locking Chock. Each chock adjusts to fit your tandem axles using the included wrench to move the footpads against the wheels. This system works with your tire movements to create greater stability. Works with wheel gaps 1.5" - 5-3/4". Zinc-plated steel. Pair. Features of Quick Products JQ-HHD1006 Locking Chock Sold per pair Zinc-plated steel Works on tandem axles with 1.5" - 5-3/4" wheel gaps One-year warranty Package Contents: Quick Products JQ-HHD1006 Locking Chock Quick Products JQ-HHD1006: Locking Chock