Strain relief is common in aviation canon plugs , but not so much on general purpose army stuff.easiest way to find them, if they are AF aviation stuff is to get the PN from the connector , there are many different types Quick disconnect QTR twist, Rachet toothed locks,with a hold down ring, Full threaded screw down with no retention except safety wire. , bulk head fittings, two piece, single unit, three piece. some shells are universal, just the rubber grommet inside and pin out changes . If your wanting to get aviation standard stuff for example , go to a 2J - T56-7 -10 T.0. Its the shop T0 for the basic engine, has tons of cannon plugs , advantage is its old stuff and there are tons around, only a dozen or so different ones, and the C-130 E model has been around forever . If your running a three wire, any male and female plug, Matched set will work, all you have to do is the pin out to serve your needs . A lot of Army pins are sauter on, Most AF stuff is crimp on, and you need an aviation full ring crimper , For 1 two or three wire stuff I use M 35A2 cannon plugs , male female and just pin it like I need it get them from Eriks and a few other common places , Main F -111 engine conectors had in the realm of forty pins or more each