A3 panels are 2'W x 3'H. Shown here is an A3-3, 3-section shield. The A3 panels are commonly used on speaker cabinets. Everything from a small combo amp to a Marshall half-stack will fit in an A3 enclosure. Click on the picture to see more examples of how the A3 can be used. Up to seven sections of A3 panels can be connected together.