There are a myriad of different manufacturers codes.PB means Beretta.BMR or BR means Breda.DRC is a US manufacturer.DRC also subcontracted for IHC and these windage knobs are marked DRC IHC.There are many others. NHC is a US code-New Haven Clock.Some other US windage/elevation knob codes that come to mind are Wright, HRA-W(Wright subcontract for HRA),SSI,LUX,BME,WCE,and there are more.The Chinese also counterfeited the BME mark.