You are buying an Insulation Displacement Connector (IDC), this product is generally known as a "SCOTCHLOK" due to first being produced by the 3M company, one of whose brand names is -Scotch-.
This product is a high quality copy of that product and is used extensively in the automotive trade for connecting cables without the need for special tools.
All that is needed is a pair of pliers!
Suitable for connecting multi-strand cable sizes 0.65mm sq - 2.0mm sq
For other cable sizes we offer a Red, Yellow & Brown versions of this item.