b:11 is an analog dual AD/AR envelope generator. It provides two identical sections, each with a gate input, an ATTACK knob, a DECAY/RELEASE knob, and an envelope output. The envelope length can be adjusted from 20ms to over a minute. Each channel can work either as an AD (ATTACK/DECAY) or AR (ATTACK/RELEASE) envelope, selectable via jumpers on the module’s PCB.