Great Planes Wheel Collars are a handy way to lock wheels on a axle. The The collars are made of brass and are chrome plated to resist corrosion for trouble-free use time after time. The collars come in 5 popular sizes and each include its own hex wrench for installation and removal. These have a Great Planes one year warranty. INCLUDES: Twelve 1/16" plated brass wheel collars Twelve 4-40 set screws One hex wrench One reusable plastic parts pack