4" x 2" Phenolic Wheel Swivel Caster w/ Top Lock Brake - 800 lbs. Capacity4" x 2" Phenolic Wheel Swivel Caster with Top Lock Brake The Phenolic wheel is made of phenolic resin and macerated canvas, which provides smooth rolling and resistance to extreme temperature shifts. Phenolic wheels are resistant to oils, greases, and some liquids, but they should not be used on rough surfaces or in wet environments. Tread & Core: Phenolic Resin Mixed With Mascerated Canvas Bearing: Plain Bore With Sleeve Rig: Zing Plated Swivel