With Cubasis I’m using a Roland Duo Capture EX interface. Sold an Alesis IO Dock when I purchased the Roland Interface. The Roland interface is more flexible than an IO Dock (can use it with a PC or Mac too) plus can run the Roland interface stand alone on AA batteries. I also use a M-Audio Keystation Mini 32 for portability when necessary with Cubasis since it’s IPad powered via USB.