1923-1924 era ... Atwater Kent type AD coil. Very Good Condition .. Small chip on one mounting lug and stains on the coil winding but the wire is still tight and solid. Uses the early style tag [like the Radiodyne sets but marked "Type 10 Transformer" and "Type AD"] ... used on the early 10 and 10A sets. The Bakelite is in great shape .. no cracks or chips. Three wires exit through the bottom of the coil .. Used on the post Radiodyne type 10 sets and also on the early type 10A breadboa...rds. Measures approx 3.75" diameter X 2.5" tall and well packed shipping weight will be 1.5 pounds from zip code 24012.