Just being zigbee isn’t enough to be SmartThings-compatible, it depends on which “profile” they use.
I didn’t see that information on their site, so the first step would be to check with the company and ask.
If it is a proprietary profile, it will only work with their own hub.
If it is zigbee home automation 1.2 (ZHA 1.2), ZLL, or Zigbee 3.0, then integration may be possible.
See the community FAQ (the topic title is a clickable link.)
Also note that some of their devices like the plug in pocketsockets use WiFi, not zigbee. Those models will not be directly compatible.