Keyboard controllers are lightweight, often portable plastic piano keyboards, ranging from 88 keys down to 61 keys 49 keys or mini keyboards of 25 keys. These can be used to play piano sounds, organ sounds, synth sounds, sampled sounds, VST instrument sounds or to trigger individual drum sounds. Some are ‘weighted’ to simulate the feel of an actual piano and some are ‘velocity sensitive, detecting the force of pressure on the keys.