This is the Walking Belt for the Xterra TR 450 Treadmill. The belt has been pre-lubricated and includes an additional application of lube. It is recommended to lubricate your walking belt atleast once a year to reduce friction and stress on the other components of your treadmill. When it comes to replacement walking belts Treadmill Doctor has been a leader in the fitness industry. Our walking belts are made from quality polypropylene materials, 2 ply construction with the backing made of polyester blended material.