This body-fitting design was developed through testing on many body types to provide optimum comfort Creeper body is 2" longer for a better fit; Urethane rollers are inserted into steel bushings which are molded into the creeper body For more information check the main Lisle tool-92102,93102,94102, and 97102 Replacement part for Lisle tool- 92102,93102,94102, and 97102