Typically a solid copper conductor in a thick jacket with continuous copper braid  shield.   

Connectors: BNC, RF, F or standard cable company  

Although when properly installed co-axial cable will transfer a wide band of frequencies with very little loss, one of the problems with coaxial cable is that long lengths can cause a slight delay in the signal.  Using different lengths in some applications (such as time critical video synchronization) may therefore be problematic.