These wheel assemblies are designed as a pair for manual mobility devices. This pair is sized 12 1/2 by 2 1/4 in., intended for manual wheelchairs and related configurations such as transport chairs, companion chairs, push wheelchairs, and knee scooters. The wheel diameter is 11.8 in., with an axle head length of roughly 2.18 in. and a bearing hole around 0.47 in. Installation relies on standard mounting points and requires checking 3 key dimensions to ensure a proper fit. The total screw length listed is 4 in., and tire width is about 1.73 in., with the rest of the dimensions described in the product notes. The tire surface uses polyurethane for durability, while the hub is made from polypropylene, and the bearing is a 6201 type, chosen for reliable rotation in typical indoor and outdoor environments. The accessory pack provides bolts and common hand tools, including a socket wrench and an open-end wrench, to support straightforward assembly of the wheels. The design emphasizes compatibility with manual wheelchairs and related devices, while electric wheelchairs are outside the intended scope. Material choices balance durability and weight, supporting practical use on multiple surfaces while keeping installation steps concise and repeatable for routine maintenance or component replacement.