This is a High current driver that will take TTL signals from your Arduino, etc to drive the relays. It includes status LEDs for each input. 5V, 12V, and 24V relay options are available. This item replaces TE-010-405 and TE-010-412
This small synchronous switching step-down (or buck) regulator takes an input voltage of up to 38 V and efficiently reduces it to 5 V. The board measures only 0.7″ × 0.8″, but it allows a typical continuous output current of up to 5 A.