Similar to the 21KA Series except with an additional safety locking system.
When being disconnected, the plug must first be pushed further into the coupler before it can be disconnected. This prevents unintentional disconnection.
This series is also available without a valve in a Straight-Thru design. For Straight-Thru Couplers, please change the part number from 21KS to 21KR when ordering.