This is a remove before flight plug, and is similar to TSM131.
An original Apollo Lunar Module (LM) hardware part, identified as "Cap Assy" (Cap Assembly), with attached stainless-steel cable and connector. The piece measures approximately 13" across (including cable) and retains its original Grumman Aircraft Engineering Corporation Quality Control Department "Do Not Remove" inspection tag, dated 8/21/69. The part number is noted as LDW420P80035-1. Also included is the original blue Grumman LM identification tag, hand-labelled with the same part number and designation. These tags confirm its origin as a component manufactured for the Apollo Lunar Module by Grumman, the prime contractor for LM development and assembly