Trionix??? High Impact Polymer - NX. These unique high impact polymer wheels deliver superior rollability, capacity and slide resistance. Trionix??? features unique polymers that resist corrosion and most chemicals. Injection molded process. NX wheels are straight sided and higher capacity than NY Wheels. Wheels are machined, not injection molded. Wheel face: Slight crown. Finish: Black. Temperature Range: -30??F to +220??F. Hardness: 78-82 Shore D.