Alesis: Drum Trigger + Amp/Footcontroller Dock for iPad
DM Dock Drum Module Dock for iPad. and the
AmpDock Multi-Effects Guitar Processor for iPad
got special addition to the well known IO Dock – Lots of Drum Trigger inputs for drummers or guitar input and foot pedal with switches and knobs – for guitarists. the drum one has 2 knobs, the guitar one 6 of them. nice to have those added.