Diameter: S60x6 Closure with valve Outlet: S60 x 6 male, standard tank valve outlet 1000 IBC/GRV tanks liters are all equipped with a low male threaded outlet where a drain valve is screwed. it is therefore advisable before any purchase of valves to take the measurements of this outlet on your tank. To take the measurements correctly, it will be wise to equip yourself with a caliper beforehand, or failing that, one meter. The dimension D1 corresponds to the OVERALL diameter of the male outlet, and the dimension P1 to the spacing between two threads if: D1 = 60mm < p>P1 = 6mm then your tank has an S60x6 outlet, you will need to buy a replacement valve with an S60x6 nut to make it compatible with your tank