The U.S. aircraft register, updated daily
Parts

Battery Master

No failure report names the battery master. 1 FAA approvals let 1 company make a replacement battery master, Alpha Aviation, INC holding the most (1).

Approved replacement parts 1 parts manufacturer approvals

A parts manufacturer approval (PMA) lets a company other than the aircraft's maker make a battery master and sell it as an approved part for the models named. These are the companies holding such approvals for a battery master:

MakerPartReplacesFitsGrantedStatus
Alpha Aviation, INCBattery Master Relay MR-12NOCDModification PartUnivair Aircraft Corp. 415-C, 415-CD, 415-D2017-02-06current

Sources: the FAA's service difficulty reports since 1995 (a report is a part that failed and was fixed, as filed by an airline, repair station or owner; the count shows reporting as much as reliability) and the parts manufacturer approvals in the FAA's Dynamic Regulatory System. The part name is the reporters' and the approval holders' own words, reduced to the first plain words so that spellings meet.