The KV331 NatLife Progressive & Deep Vol 1 Expansion Pack is a library of sounds for the SynthMaster One virtual instrument (available separately) with an emphasis on the progressive spectrum of electronic club music. The pack provides 50 presets created by NatLife with sounds focused on melodic techno, progressive house, and progressive trance musical genres. Sounds include synths, pads, leads, basses, and percussion, along with arpeggiations and sequences.