This is a 4-Way Wrench with Plug Storage. It can be used to tighten and loosen glow plugs and prop nuts or any nut in the proper size range. FEATURES: It has storage for 3 glow plugs (it helps them stay clean) It will work with both standard and metric sizes, 3/8,10mm, 1/2,12mm 5/16,8mm, 7/16,9mm. The glow plug wrench is extended for taller cylinder heads. Chrome plated. INCLUDES: One 4-Way Wrench w/Plug Storage dew 10/18/01 ir/jl