 An additional 4 veto layers of the scintillator surround the module on the sides to distinguish particles entering from the outside from those produced by interactions inside the module.The total mass of iron in one module is 7.1 tons and constitutes 96% of the module weight.On the neutrino beam axis, in the middle of the cross between the vertical and horizontal arm, there is an additional module built only from layers of the plastic scintillator (Proton Module) with a mass of 0.55 tons.