The 81532102 is an associable sub-base designed for DIN rail mounting in modular pneumatic timer systems. It features rotable push-in connections (Ø 4 mm) for semi-rigid tubing and allows multiple products to be connected next to each other in a daisy-chain configuration. The sub-base includes three instant connection ports: an input port (green port 1), an output port (red port 3), and an input/supply port (yellow port 2), along with an integral input port. The unit is equipped with 1/4 turn screws for secure assembly, mounting tongues and grooves for alignment, and a selector for flow direction indication. This modular design enables flexible pneumatic control system configurations while maintaining compact footprint on standard DIN rail installations.