Notation for number of tensor permutations

I have a tensor (or set if you will) that consists of N elements, and each element has a limited number of values it can take. For example:

T = {A,B,C,D}, where A=[0,255], B=[0,255], C=[5, 25], D=[5,35]


The total number of unique permutations for this tensor are thus 256*256*21*31 ~ 44million What is the notation for writing this?

?T? = {256,256,21,32} ????


I'm pretty sure its not |T| as that would be 4, i.e. the number of elements in T right?