This module is a bi-directional SPSD (Single-Pole, Single-Throw), normally open solid state relay (SSR). The Grove Optocoupler Relay (M281) offers very low on-resistance, which allows a high load current rating in operation.
Unlike the other TRIAC SSR relays available, this one is based on a MOSFET, which means it can carry both AC and DC loads. If you need to use an SSR with a DC load, this is the relay you've been looking for!