The Tibbit Block #03-1 2Channel Low-Power Relays are blocks of prepackaged I/O functionality housed in brightly colored rectangular shells. It is the Tibbit blocks that give the Tibbo Project System (TPS) its flexibility.
They are rated for 1A/30V. To activate a relay, set the corresponding control line LOW. When left unconnected, control lines default to HIGH (and, hence, relays are off). Combine this Tibbit with terminal block devices — #20 (nine terminal blocks) or #21 (four terminal blocks).