red 1 uds one way check valve aquarium pump accessories matching 4mm air pipe

red 1 uds one way non check valve aquarium air pump accessories compatible with 4mm large function gas pipe characteristic: safe and durable products one way check valve of aquarium air pump protect your air pump to prevent the water in the aquarium from moving backward in case of power failure. placed on the air duct between the air pump and the aquarium to prevent water from returning from the air duct. made of durable plastic, small, compact and easy to install. matching with air pipe