These are handmade, hand-wired clones of an old school sustain "module" originally made in the mid 70's by a great NY effects company. These were a cut-down version of the famous fuzz/sustain pedal made in a small box to plug straight into your guitar. The circuit is VERY similar, using the now famous JRC4558 Op Amp, like the original, although I have added a volume control for more versatility still. This version is in my hand made custom built stainless steel enclosures with true bypass and LED.
These are a thick fuzz with a fairly flat mid response and good bottom end. The silicon diodes are driven into nice break-up and there's a slight gate to the sustain. Check my blog for more details.
My designs are inspired by the classic old units but with modern components and appointments and many options like true bypass or non-true-bypass switching, LED's, added "active" tone controls, boosts and "Boss" compatible 9-volt adapters. NONE of my pedals use batteries.