4" Single Arm Fill Cap with Brass Padlock (Keys alike). A fill point cap with captive padlock compatible for use with Hexagon Part A MIL - C - 27487. Brass Hasp Padlocks - keys differ. Innovative cap robust construction with gravity die cast Aluminium LM4
Note: This fits on a 4" Adaptor.
The actual outside diameter of the cap is 5.5"