The new Keeley Electronics Neutrino Envelope Filter employs a compact circuit based on an opto-coupler and has controls for input Gain, resonance Peak, Filter selector, tone Range, and Drive direction. Hand-built in the U.S. and housed in a powdercoated enclosure, it has true-bypass switching and its side-mounted/recessed Drive switch and internal output Volume keep the look clean. Visit www.rkfx.com.