3.5mm to SMA adapters are useful even though in theory perfect 3.5's & sma's mate mechanically. The 3.5mm has an air dielectric and will work to 34+ ghz. Precision SMA's have a teflon dielectric and will work to 27ghz. Always use SMA to 3.5mm adapter connector savers like these when connecting an sma to a 3.5 as an out of tolerance sma can ruin a 3.5mm. Using 3.5mm to sma adapters as connector savers avoids potential damage to 3.5mm connectors. Our 3.5mm to sma adapters are stainless steel bodies , with BeCu female contacts.