material: free cutting brass is 319 type (l) free cutting brass as per bs 249 type (i) generally free machine grade of cuzn37pb3 equivalent to bs 2874 is used to manufacture various brass threaded inserts in form of round, hexagon, square etc other grades which are followed as per custom requirements are cz 121, cz 131, c3604, cda 360, and dtd 627 etc high grade free cutting brass. any special brass material composition as per customer’s requirement.