This durable variable gap magnet l is fantastic for demonstrating and researching electromagnetism. It can be used to demonstrate induced currents as well. It is 5.25" in length, 4.25" tall and 2" wide. Each screw is 3" long with a 1" diameter. The field strength can be adjusted between 100 and 7500 Gauss and the screws can be varied between .4 and 8.5 cm. The supplied flat pole pieces are 2x1x1/8" and can provide a more uniform field when necessary.