25mm male and 20mm female Brass tank flange adaptor (1/12" x 1 1/4")
Our Watermark Approved brass tank flange adaptors with EPDM rubber gasket are used to provide a secure and waterproof connection to any brand of poly, steel or plastic water tank. These adaptors (also known as a tank boss) are very well made with a nice thick 3mm seal so you can be sure that it will stay exactly where you put it. The male BSP thread is all one size up to the female BSP end of the unit. The threaded end is actually threaded outside and inside so it is 1" male BSP outside and 3/4" female BSP inside. The 1" locking nut has a reverse thread (a left handed thread) so when you install a ball valve on the male thread, it automatically tightens the fitting on the tank wall.