Standard quality treadbelt used on Cybex models 450T, 500T, 515T, 520T, 530T, 550T, 600, 640, 700, 700T�treadmills. With 60" walking surfaces.� Units with serial numbers�GREATER than model 500T = X07-07520T9814NN, model 515T = �X07-07515T9514NN, model 520T = X07-07530T9814N, model 530T & 550T�= X07-07530T9814NN �NOTE: We strongly recommend you apply lubricant when you replace any new treadbelt.