THIS HEAVY DUTY EASY ROLLING WELL BUILT LONG LASTING CASTER FITS ALL SNAP-LOC DOLLY SYSTEM PRODUCTS AND IS THE PERFECT REPLACEMENT CASTER FOR UPGRADING OTHER DOLLIES AND CARTS. THE SNAP-LOC DOLLY SYSTEM IS THE EASIEST FASTEST AND SAFEST WAY TO MOVE MORE IN LESS TIME THE PROBLEM CHEAP DOLLIES HAVE JUNKY CASTERS THAT DON'T ROLL WELL BREAK OFTEN CAUSING VALUABLE ITEMS TO DANGEROUSLY FALL AND WASTE YOUR TIME AND MONEY. THE SOLUTION THE SNAP-LOC DOLLY HAS HIGH CAPACITY SMOOTH ROLLING CASTERS IS USA MADE TO LAST A LIFETIME OFFERS E-TRACK STRAP CARGO ANCHORING WITH PUSH-PANEL BARS THAT TRANSFORM TO MOVE EVERYTHING WITH EASE YOU'RE GOING TO LOVE IT DOLLY SYSTEM ALSO COORDINATES WITH THE SNAP-LOC E-TRACK SINGLE SYSTEM TO SECURE CARGO AND ITEMS ON PICKUPS TRUCKS TRAILERS RACKS WALLS FLOORS CEILINGS AND MORE EASY ROLLING PRECESSION BALL-BEARING 6 INCH SOLID RUBBER CASTER WHEEL WITH TREAD FOR USE ON HARD SURFACES DIRT GRAVEL GRASS AND MOST FLOORING. 360 DEGREE SWIVEL WITH FOOT BRAKE. HEAVY DUTY BUILT TO LAST INDUSTRIAL RATED THICK STEEL ZINC PLATED CONSTRUCTION RESISTANT TO MOST CONTAMINANTS/WEATHER. TOUGH HARD SMOOTH WHEEL FOR SUPER-DUTY MAXIMUM CAPACITY. VERSATILE SOLUTIONS SLOTTED TOP PLATE FITS INDUSTRY STANDARD 2-3/8 X 3-5/8 INCH. BOLT HOLE SLOTS 1-3/4 X 2-7/8 INCH ON CENTER. GREAT REPLACEMENT ON 4 WHEEL DOLLY CARTS PLATFORM TRUCKS PANEL CARTS.