M5/M8/M9/M12/M16/M23 connectors with screw threaded joint, circular connector, waterproof rating is IP67. 
Protected from dust and water during immersion, resistant to many oils and chemical. 
Professionally for inductive or capacitative proximity switches, sensor devices and actuator devices. 
Plug design as per IEC 61076-2-101 
M12 a /b/c/d coding assembly connector 
Connector series: M5/M8/M9/M12/M16/M23
Coding: A /b/c/d /x
General information: 
Standard: IEC 61076-2-101 ED 3.0 
Connector body: PA66+gf or TPU 
Connector contacts: Brass with gold plated 
Shell/nut: Brass with nickel plated 
Insulation resistance: ≥ 100m 
Waterproof rating: IP67/IP68