OTC's 4254-FR heavy-duty suspension bushing adapter kit works in conjunction with OTC 4247, 4275, 4261, or 4263 service sets (not included) to replace worn-out, rusted, and frozen single-wrap and double-wrap spring bushings. Adapters included in this kit are compatible with, and allow for service of, the following applications: Hendrickson rear suspensions including: Primaax EX, Comfort Air and FCCC V-Ride pivot and D-pin suspension bushings. Compatible with (continued): Freightliner rear suspensions including: Double and single-wrapped FAS II Airliner rear suspension bushings. Rugged materials stand up to repeated use and ensure reliable performance and a long service life. Adapter set only - must be used with OTC 4247, 4275, 4261, or 4263 service sets.