Free Cutting Brass IS 319 Type (l) Other grades which are followed as per custom requirements are CZ 121, CZ 131, C3604, CDA 360, and DTD 627 etc. Any Special Brass Material Composition as per customer’s requirementThread as per International Go and Not Go Gauge Standard. Deep Groove for maximum Pull out Resistance. Inner Diameter (ID) after threading with very close tolerance to prevent unrequired flush to enter.