These N to TNC adapters come in both 11 and 18Ghz versions. The 11 ghz parts use "standard" N's and TNC's, as called out in mil-specs. The 18ghz version of these TNC to N adapters use precision N's, & precision tnc's. The precision tnc to n adapters are made of stainless steel & use the TNCA interface. The standard versions of these N to TNC adapters use brass for their bodies.