These are pluggable terminal block connectors. They are light in weight and highly insulated for short circuit protection. They have a Nylon 66 material body and the metal parts are built from phosphor bronze material. These connectors are used to connect wire and cable to the circuit board. The male connectors can easily mount on a PCB board. The female connectors have screws to hold the wires. When the female connector interlock with the male connector, a strong bond is established and the current flows through them. These types of connectors are very useful in hot-swapping types of applications. In other words, They are used where the connection may be expected to be removed for servicing or any other purposes.