These crimp butt connectors are great because they heat shrink also. Heat shrinking these help hold the wire more securely and just give it a nice seal and neater look. Four sizes and a total of 350 in all. They come in a nice plastic organization box that has two snap closures that close extremely well. I had a bit of difficulty to open these clips and was quite surprised because most just pop open way to easily and that can be a huge problem causing you to spill/dump the entire box and then you hatto sort them and replace them in the plastic box and that is no fun at all. So I would much rather the snap closures are difficult to open than not. I would much rather them to be secure than not. The four colors help to identify with the wire gauge size they are intended for and they are marked on the side of each connector also. I really like the quality of these butt connectors too. They are alot better than I expected and I am extremely pleased with this purchase and I am quite sure you would appreciate their quality as well. I believe the affordable price is what makes these such a fantastic value and a great addition to your inventory of electrical repair and construction equipment tools supply parts.