This device is for airplane modelers who have their engines and fuel lines in "hard to get at" places such as cowlings. FEATURES: One-piece valve assy. installed into airplane with convenient fueling probe for refilling. INCLUDES: One Pre-assembled Filling Valve One Fueling Probe (GPMQ4162) One knurled nut w/serrated washer SPECS: Overall length (front to back): 13/16" (20mm) Mounting nut diameter (what is seen on outside of cowl): ¼" Hole size (drilled through cowl): 3/8" Length inside cowling: ½" Thread pitch .45mm Inside diameter .92mm (.363in) COMMENTS: Will require drilling 3/8" hole for acceptance of valve assembly. NOTE: This will ONLY work with Glow Fuel For GAS Easy Fueler use GPMQ4161 The measurement for the valve NUT is as follows Pitch-(.45mm) Inside Diameter- 9.2mm (.363in) jct09/22/00