Designed specifically belt return applications in 3.5 OD x 14 ga. tubing. Recommended for high speeds and quiet operation. The radial ABEC bearing is assembled in the outer housing for easy installation. The hex adapter eliminates metal-to-metal contact between the bearing and axle which reduces noise during operation. The radial bearing includes metal shields for protection against dirt with less rotational drag than rubber seals. The polypropylene housing limits load capacity and is sensitive to heat. Not recommended for heavy loads or high temperatures.