OTC Ford Diesel Engine Compression Test Adapter For use with OTC's No. 5021 diesel engine compression gauge This adapter is used to connect the No. 5021 gauge to a glow plug port (after the glow plug has been removed) for performing a compression test Fits 1994-2003 Ford pickups and vans with 7.3L direct-injected turbocharged (DIT) diesel engines Similar to Ford 303-D103; high-grade materials ensure quality performance over the lifetime of the tool