ScotchLok, ScotchLok, electrical connector with mortise contact.
This is for low voltage (network, telephones, LED lights, etc.).
The point is simple - several wires are pushed into such a thing.
After which it snaps into the pliers or any oppressive tool.
They are especially loved by the installers of the SCS and networks, for simplicity, cheapness, water resistance, and the lack of the need to remove the insulation.
Inside - a hydrophobic gel that protects against corrosion, moisture, oxidation, etc. And a plate with a cutting-clamping surface or two plates.
What happens to the cable after installation?
Knives cut the insulation, and firmly pressed to the wire.
There is also a version for two cables at once.
By itself, they are disposable and maintenance-free. It is necessary to replace - a piece of cable is bitten off with them, and a new one is put.
Cost: from 2-3 up to 5-7 rubles apiece.
P.S. They are very convenient to use - it is not necessary to remove the shell of the wire, just shoved the wires into the scotch-loop and pressed the passatages (knives inside the tape loop cut the insulation, and tightly pressed to the wire). There is one but - 4 wiring in USB cable is very small in diameter and therefore sometimes they slip between the scotch-log knives (it is usually enough just to strip the tape-lok passage, so that it cuts the wire insulation, but sometimes it does not drive and you have to cut a piece of wire and use new scotch-slope).
At first I, until I got used to using them, spoiled about 10 scotch locks. Now I got it and it turns out the first time. Usually the problem is that you did not shake the scotch-lok, you just need to press the pliers harder. Therefore, take them more than you need, just in case.
You can buy them at an electrical goods store, a radio goods store or in the construction market.