avionics

Hi Everyone I'm new here this is my first post so excuse me if I've not posted in the correct format. I have recently purchased several small bomb release catches. Not sure if they come under Avionics as they are electrically triggered? I'm trying to get them working from 28v DC power source but...

Newbie here. (Sorry for the previous large images) My late husband worked for Sperry during WWII and collected several instruments while he worked on bomb sites. I have been able to identify all but one. The attachment does not show everything. Besides the obvious numeral "4", in black font on...