I just recently bought a box of the Raco 4714 "Insider" inside-the-box connectors for the first time. I think these have been around for a while, but I can’t say that I’ve ever used them before. These are neat for old work, like fishing a wire into a box or panel that’s flush mounted in a finished wall. They have a pretty good range of wire combinations and I particularly like that they are almost perfectly flush with the inside of the box when installed, so they don’t take up any additional space when used with something like an octagonal box. Seems that Hubbell currently only makes them for 1/2" K.O’s., but it would be great if they could also offer them in 3/4" and 1" to handle 8/3 and 6/3 NM. I know Rack-a-tiers has made a similar type of 1/2" NM cable connector for years, but I don’t really like how far theirs protrude when installed from inside the box.

Raco Insider