This is an authentic Jet replacement part, sourced from the original manufacturer for use with thickness planers. The special retaining ring is used to secure the bushing along the lead screw shaft. This retaining ring is available as an individual replacement part, please see illustrated part list for related parts. For Use With: Jet 15S (1791210) 15" Spiral Cutterhead Planer 15HH (1791213) 15" Helical Cutterhead Planer JWP-15DX (708538) 15 in. Thickness Planer JWP-16OS (708531) Woodworking Planer JWP-15CS (708538) 15 in. Thickness Planer JWP-15HO 15 Inch Planer JWP-15CS (708529) Planer