These Lumex fixed wheels are designed to convert standard folding walkers into wheeled walkers for easier mobility. The 603630A and 603650A are standard replacement wheels for 1-inch tubing, offered in 3-inch and 5-inch sizes respectively. The 603750A includes an extension leg for greater height adjustment, while the 603950A is specifically engineered for bariatric walkers with reinforced materials to handle higher weight loads.