I got this marker by complete chance on eBay, when I happened to see a listing for an ACI Griffin, but noticed the odd gadget mounted on the back. That odd gadget is the Sonic Conversion, a omplete Electro-Pneumatic kit for the griffin. The cylinder on the rear contains a regulator, pulse valve, and ram assembly. It receives air via a nylon airline connected to a volume chamber on the front. The trigger is a simple momentary switch connected to a 9v battery, there is no control circuitry. The system uses the solenoid to trigger the firing sequence, but the timing of the system from there is pneumatically controlled.
Besides the inherent rough edges in conversions like this, the Sonic kit has a shelf life of sorts, the volumizer is not rebuildable and contains an oring. Once that oring fails you will have to create your own air supply.
