This "T" plate allows for the addition of the BA-TG ball (in the upper part of the picture), therefore allowing for the addition of arms or a focus light.
**Please specify the type of housing to receive the proper screws.**
We dive with our products all the time. Please call the Bluewater Photo team at 310-633-5052 with any questions, or email us at sales@bluewaterphotostore.com.