This is mil-spec 50 ohm RF cable made by Harbour Industries. This is type M17/93-RG178. This cable is silver plated copper with PTFE teflon(R) insulation. The OD of this cable is 0.0695 inch (1.77mm).   If you buy more than one of these I will ship it as a continuous length.  This is a 50 foot length of wire.