 Electronic and digital keyboards that imitate the sound of the Hammond are referred to as "clonewheel organs".The first attempts to electronically copy a Hammond appeared in the 1970s, including the Roland VK-1 and VK-9, the Yamaha YP45D, and the Crumar Organiser.The Korg CX-3 (single manual) and BX-3 (dual manual) were the first lightweight organs to produce a comparable sound to the original.