The A-170 module from Doepfer contains two independent slew limiters, also called slew limiters or portamento controllers. The upper unit has a common control for the rise and fall time. The lower slew limiter has separate controls for rise and fall time and can thus also be used as a simple attack/release envelope if a Gate is fed instead of a CV. Furthermore, a 3-step selector switch allows you to set three-time ranges for the rise and fall time. Both units have two LEDs each for control indication of positive and negative signal components.