You can follow below factors to choose your shielding enclosure.

1) The inner size of the shielding enclosure, it depends on your DUT(device under test).

2) The operation of the Shielding enclosure, Manual, Pneumatic, Semi-automatic. Also it depends on your usage.

3) The connector you need such as DB9/DB25/RJ45/USB /SMA/ etc. We can do the customized connector at economical cost. 

4) The frequence of your DUT(device under test).

5) The shielding effectiveness you need for your DUT(device under test).

6) Other specific request if you have.