Spring reverb tanks. Three sizes with three different sonic characteristics. If you have a Springray2, you'll need at least one of these tanks, but know that you have enough connections on a single module for all three tanks!
This adapter lets you to connect either one or two Pedal I/O modules to a 1st generation audio jacks board in a 7U performance case. It is not needed if your case contains a 2nd generation audio jacks board.