The malletKAT is the world's most powerful MIDI percussion mallet controller using true FSR sensing technology. The GOLD malletKAT Grand offers a standard lightweight 4-octave design which can be expanded to 5 octaves. This is the same lightweight metal first introduced in the MalletKAT Express series. It incorporates the same FSR technology as all of the KAT instruments, delivering superb feel and response. With 127 programmable setups and features like splitting, layering, poly/mono and "hang" modes, the malletKAT is an incredibly expressive and powerful alternative to traditional marimba and vibraphone instruments. This new malletKAT Grand 7 KS has a brand new sound engine developed by the world famous Kurzweil Music Systems. The sound set comes from their new PC3 sound library. Quality instruments.....hundreds of them..... now built right inside the malletKAT. We redesigned the amp board inside the malletKAT as well, so now the stereo audio outputs are professional quality balanced outputs with clean pure sound! The KS model has a headphone jack plus two audio outs in addition to two audio inputs to allow mixing in of outside audio sources for practice or performance.