Gretsch G9200 Round Neck Resonator Novation The other two knobs are

The other two knobs are simply Delay time and Feedback

or other hardware

The PLUS Pedal offers full control over each layer of sustained sound

we finally arrived at a design that earned its colors and has the elusive magic of this historic pedal

Gretsch G9200 Round Neck Resonator Novation The other two knobs areWith its mahogany "long body" design and comfortable "soft V" shaped neck, this faithful reissue of the 1930s classic sounds and plays like a million bucks. The vital feature of all Gretsch resonator guitars is the Gretsch Ampli Sonic diaphragm (resonator cone), which is hand spun in Eastern Europe from nearly 99 percent pure aluminum, yielding an impressive quality and volume of tone. Back & Side Wood: Laminated Mahogany Top Wood: Laminated Mahogany