3M R/Y+BOX Performance Plus Wire Connector, 100 per Box

These things are great

This is my first time using these. They seem to work well. Even though they cost a little more, I like that it covers 2 different sizes of wire nuts. It takes some of the guesswork out. For the project I'm working on right now these should work everywhere a wire nut is needed (except ground. I'm using greenies for those in some tight places). It will probably take me a while to use all of them, so it may save me money in the long run vs. having to buy and keep track of 2 different sizes.

These connectors are far and beyond the best I've ever used. I'm not a professional electrician, but an avid DIY-er. I've re-wired most of my house using these, and I love 'em. I noticed that electricians seem to use these, so I gave them a try. These have a really great bite and hold on connected wire that no other product can touch. This is pretty important, as I want to know that any connection I make is going to stay, and with these there is no doubt - connections are really firmly made and it is very hard to pull off the connector once it's twisted tight. I've used all of the brands you can buy are your local big-box stores, and none come close. The flexible skirt on these is nice as well if you are working in a tight place. I'm not going to bother looking anywhere else for connectors.

They hold wires very well but are quite big for smaller boxes. I used them for led pot lights and they were a fight to be able to close the box.

Not an electrician, but I have a lot of outlets and fixtures to wire right now. The actual electrician who put in the new wiring had left a handful of connectors with rubber skirts. I liked the idea of them, so I went in search of more but couldn't find any locally. I'm presently working my way through a box of these 3M connectors, and so far they've been great -- they really do get a good grip on the wires. A recurring issue I'd been having with putting light fixtures on the older '40s wiring was that the copper often shot right out the tip of other nuts after a few hard twists; it's still early days, but so far that's yet to happen with these 3M connectors. Nice! So it's seemed worth it to pay extra for them.