We have examined a promising family of radio frequency coaxial connectors (the SSMCX range) suitable for use at low temperatures. We describe the measured characteristics of these connectors in typical arrangements using lossy Cooner stainless steel inner and outer (braided) coaxial cable and other specialty low temperature coaxial cables including Beryllium Copper (BeCu) outer and inner conductors, Copper Nickel (CuNi) outer and Niobium–Titanium (NbTi) superconducting inner conductors, and Nb outer/NbTi inner conductor (homemade) cables. Of these, the BeCu coaxial cable proves to rank among the smallest losses consistently from 300 K down to 4 K. We also characterize Copper, BeCu, and CuNi clad NbTi braided twisted pair “looms†demonstrating that CuNi–NbTi is the most practical choice due to minimal heat leak. © 2012 Elsevier Ltd