The Apex Plastic 25mm Long Tail keeps tanks and troughs topped up through an extended threaded inlet. The long tail provides the through-wall mounting connection.
The long tail is the extended threaded inlet that passes through the tank wall. The arm is the lever connecting the valve to the float; the short-arm version needs less space inside the tank.
Allow enough room for the float to rise and fall freely. Check the drawing for this tail and arm before fitting.
Float sold separately. The recommended float is a 150mm Apex ball float in black or orange.