This is a "Whisper" Aquarium Inline Airflow Control Valve by TETRA - 2 Pieces included. It is made in plastic and can be secured on an aquarium rim of up to 1 in. wide. The air flow of airline is fine adjustable with a turning knob. The airline connectors can be rotated to suit the aquarium setup. It comes with an end cap. Pick up only from Cobble Hill.