If you purchased new Tefillin, the cases are always included. Tefillin come in several sizes. If you sent us your Tefillin for inspection and you would like to replace your cases, just select the "Fit to Tefilin" option, and we will adjust your Tefillin with its proper case size. If you are just purchasing cases and we don't have the actual Tefillin for a proper fit, then select one of the available sizes below. 34cm is the most common size today. If you can not determine the proper size, contact us and we will try to help you.