Dimensions: 
Each quartered hull =
6 in. wide x 8.75 in. long x 1 in. deep.

The inner-rim clamping surface =
I in. wide x 1/4 in. deep

Accommodates a typical 6" to 8" architectural in-wall speaker.

Installation:
Sand-fill each quartered hull via the fill-hole.
(Use clean dry sand. Avoid beach sand)
Secure each fill-hole with supplied wood plug.

Insert each quartered sand-fillled hull through the custom speaker cut-out.
Use an adhesive such as 3M Strip Calk to hold in place.
Poster putty is sufficient for the in-ceiling model. 
Insert and clamp the speaker to the SandTrap inner-clamp-rim. 

We modify/cut a funnel slightly smaller than the diameter of the Sand-Trap fill-hole.
This minimizes the insertion depth which provides easier sand flow.

We have provided a "string hole" in each hull.  Insert string or fishing line through the hole.
This allows the retrieval of a hull accidentally dropped in the wall.