The wk4 operating manual is the one you require its the same as wk4. If you download the latest operating system from www.generalmusic.com go to gem keyboards and find the link for software it can be downloaded free of chrge. It is also in the support section on gem club site. You need to download the WK4 plus operating system this is the latest version and will make your wk4 a plus model. It enables the option button to fucntion giving you a full sample translator and sound edit facility.

Darren