These SMA to BNC RF Coaxial adapters are quite commonly used in both test labs and in systems. Our bnc to sma adapters either use a brass sma, or stainless steel sma. Mil-Spec's call out Stainless steel sma's; in the commercial world brass sma's are common. Be sure to not tighten brass sma nuts over 5 in-lbs when choosing brass sma to bnc adapters as damage to the sma can result. We specify these bnc to sma adapters through 4Ghz, though in the lab in nonvibration environments the sma to bnc adapters easily go past 8Ghz.