Replacement "Balloon/Beach" tires. Sold in sets of two. Fits Malone MPG521-S, MPG522-S, MPG564-S and MPG576-S carts.
VEVOR 2-Pieces Beach Balloon Wheels 13 in. TPU Cart Sand Tires w/32 in. Stainless Steel Axle and Free Air Pump for Kayak Dolly STLYCDZCBDD124PPJV0 - The Home Depot
2X Balloon Wheels 16" Replaces Big Beach Sand Tires fit for Kayak Dolly Canoe | eBay