There are various types of terminal blocks. One type of terminal block accepts wires that are prepared only by removing (i.e., stripping) a short length of insulation from the end. Another type accepts wires that have ring or spade terminal lugs crimped onto the wires. Printed circuit board (PCB) terminal blocks allow individual wires to be connected via solder to a circuit board. While there is a wide range of product style, this course will focus entirely on industrial terminal blocks that are secured onto a mounting rail, known as DIN rail. The metal components of DIN rail terminal blocks from Phoenix Contact are made from high-grade copper alloys to prevent strain cracks and corrosion. This eliminates the possibility of electrolytic corrosion in the presence of moisture and risk of rusting. This also ensures reliable electrical contacts. Another advantage is low temperature rise for good electrical conductivity. The surface of the metal parts is protected by lead-free, galvanic nickel or tin plating. The insulation housing of terminal blocks from Phoenix Contact is made from Polyamide 6.6, an elastic nylon plastic with positive properties of high impact strength, halogen-free and UV-resistance. Additional qualities include chemical resistance and excellent aging characteristics.