The STC and STS SORBER baffles are most commonly used as lid sections. The STC4 and STS4 are 2' wide x 4' long. The STC5 and STS5 are 2' wide x 5.5' long. STC412 and STC512 are 1' wide each. STC sections are rectangular, while STS sections are trapezoid shaped.
The STC4 and STC5 can also be attached to walls and ceilings as acoustic treatment.