using results of drinfeld and taguchi, we establish an equivalence of categories between the category of ``drinfeld displays'' (objects to be introduced) and the category of $\pi$-divisible modules. we define tensor products of $\pi$-divisible modules and using the above equivalence, we prove that the tensor products of $\pi$-divisible modules over locally noetherian base schemes exist and commute with base change. if time permits, we will show how this will provide tensor products of lubin-tate groups and formal drinfeld modules.