The Monstrum G3 Series G3FFPS2x56 First Focal Plane Rifle Scope is the next evolutionary step for FFP scopes Full MultiCoated Crystal Optics The 2x magnification is capable of close to long range targeting at distances of up to 1500 yardsThe following as a Tap drill size table and chart for Whitworth pipe thread per DIN ISO 228 All dimensional data given in mm (millimeters)The male BSPP, G 3/8 thread seals with use of an FKM (Viton) oring The body of male elbow stainless steel push in fitting with oring can be rotated after installation 10 mm x BSPP, G 3/8 90 degree male elbow stainless steel push in fitting is made of 316 stainless steel for corrosion resistance, FKM oring for chemicalresistance 10 mm OD Avta10 Thermostatic Valve 2m O18 210 Mm G3 8 003n11 G 3/8 in mm