We consider the class M of R{modules where R is an associative ring. Let A be a module over a group ring RG, G be a group and let L(G) be the set of all proper subgroups of G. We suppose that if H 2 L(G) then A=CA(H) belongs to M. We study an RG{module A such that G 6= G0, CG(A) = 1. We consider the cases: 1) M is the class of all artinian R{modules, R is either the ring of integers or the ring of p{adic integers; 2) M is the class of all nite R{modules, R is an associative ring; 3) M is the class of all nite R{modules, R= F is a nite eld.