Dual invariant theory of particles with spin 1

The aim of the work is the construction of a vector field theory without superposition of additional conditions on a field function and possessing a group of inner symmetry. Six-component theory of the vector field is suggested. Antisymmetric tensor of the second range is used as field functions. The theory is invariant under a group of dual transformations. Equations of motion have hyperbolic and causal nature when including electromagnetic interaction. Structure of operator algebra leads to representations in space with indefinite metrics. Analysis of tensor of spin momentum shows that spin of field has a value equal to 1