The AF49FD is a panel board front trim from the A Series (AF family), sized at 49-1/2 x 20 inches. It ships as a flush-mount trim with a front hinge to the box, enclosed to NEMA 1 — indoor drip-and-dust protection, no gasketed seal. No holes in the box: the trim, hinge hardware, and mounting provisions are what you get in the carton.
Flush-mount trim means the front face sits level with the finished wall surface — no protruding lip. The 49.500 in height and 20 in width match the corresponding A Series panel board enclosure. Front hinge allows the trim to swing open for breaker access without removing the entire cover. NEMA 1 rating suits indoor electrical rooms, warehouses, and light commercial panels where drips and incidental contact are the only exposure.