This pump integrates the following devices:1 - Streamlined impeller. High flow and low current draw.2 - Built-in circuit breaker.3 - Non-return valve (except 16.483.12/16.482.12). Prevents water backflow from the drain pipe;4 - Vent integrated in the pump body to prevent air bubbles in the circuit and to work in pair with the check valve.5 - Drain threaded hose adaptors for easy installation.