When you're not touring your PA for one-night stands, you don't always need flexible speaker cable with a protective rubber outer to help with both protection and cable wrapping.
So for permanent installation of amp racks and speakers, choose Figure-8 speaker cable (it's far more cost-effective than other solutions).
TSAW653 is 2 core, with coloured PVC insulation (RED and BLACK) on the inner cores for easy +/- identification.
The conductors are 4.6mm² (AWG 11), and the whole lot is protected by an outer PVC sheath, in a 'flat figure-8' configuration. TSAW cables are based on a 0.3mm conductor strand.
Nominal OD = 5.8 x 9.9mm
For smaller amounts, try TSAW653 (per metre pricing, cut to the length you require)