Features 1、Simple operation, most serial commands are single‑byte commands. 2、With capacitor filter circuit, which has improved stability. 3、Onboard 2 relay, which can be accessed extended 2‑way relay module. 4、Two‑channel relay, plus two expansion IO ports, low‑level output. 5、Built to meet standard specification, strictly follow factory quality control. Specification Condition: 100% Brand New Item Type: Relay Switch Board Material: Plastic Color: As picture shown Two-Channel Serial Relay: Channel: Two-channel relay, plus two expansion IO ports, low-level output Interface: DB9 female/male RS232 level, can control the relay on, off, self-locking, inching through the super terminal (serial port debugging software) on the computer. Control Current: 10A Package List 1 x Relay Switch Board