Marathon, 4.00-6 Easy Fit Pneumatic, Air Filled, With Wheel Assembly For 4 CUFT Wheelbarrows & Other Residential Wheelbarrows & Carts, 1.75" Centered Hub, 5/8" Ball Bearing, Includes Spacers To Convert 1.75" Centered Hub To 3" Or 6" Hub Lengths, Inflate With Manual Pump Only, Not For Highway Use.