M17 to M40 PRO Circular Connectors Phoenix Contact M17 to M40 PRO Circular Connectors feature a secure ONECLICK fast-locking system and consistent connector design, which is backward compatible with various manufacturers. The connectors provide reliable shield connections with cost-effective cable assemblies, which are ideal for power and signal transmissions. The M17 to M40 PRO series connectors offer 6 to 19 positions for system design flexibility. The Phoenix Contact M17 to M40 PRO Circular Connectors are IP66 and IP68 rated for harsh environmental conditions and operate with 20g minimum vibration resistance.