Application Perfectly compatible with 2003-2006 Ford pickups and vans with 6.0L powerstroke diesel engines. High Performance Specially designed to connect the part number 5021 diesel engine compression gauge to a glow plug port (after the glow plug has been removed) for performing a compression test. Direct Replacement Comparable to OEM part number 6660 303-757 both in quality and functions. Used with J-6692-B 303-D092 AM-303-D092 J-26999 compression test gauges. Superior Material Made from top quality RUBBER and STEEL, high strength, prevent corrosion and rust, wear resistance, sturdy and durable. Meets or exceeds OEM specifications, ensures long-term reliable service. .