After you order the cage they send you an email with an invoice that they want you to confirm your order is correct before they start fabricating it... at this time you will have the opportunity to ask them for the modification.

The T8 measures:

48 1/8" x 23 1/2" x 11 3/4" on the outside. All of the walls are 1/2" thick so the inside dimensions of the cage are 47 1/8" x 22 1/2" x 10 3/4"