The TD20S Drum set which is the highest V-drums that Roland has to offer with new TDW20 expansion cards. With 50 new drum sets inside it provide different ambiances. The TD-20 sound module has improved mesh-head V-Pads™, highly acclaimed V-Cymbals™ and innovative new V-Hi-Hat for complete playability. The HD1 drum set is the entry level model called the V compact series and has ten drum sets and designed with five variation push buttons on the front. These are really amazing drums. Check out www.roland.com for more exciting products.