Wyze, the makers of one of the cheapest and most capable smart cameras on the market, is entering into a new category: home security systems. The new Wyze Sense system is an equally affordable set of sensors for monitoring entryways into your home, including doors and windows, and keeping track of any unusual motion activity. The whole system, including two contact sensors and one motion sensor, costs just $20.

The whole system works via the existing Wyze Cam line. Bundled with the three sensors is what the company is calling the Wyze Bridge, which connects to the back of one of the company’s existing cameras, either the Wyze Cam or Wyze Cam Pan, to connect the whole setup to the internet. From there, you can monitor everything through Wyze’s mobile app.

The sensors themselves can activate the Wyze Cam’s recording feature when movement is detected, while the contact sensors can let you know how long a window or door has been left open. You can also adjust the settings so that you can be alerted to any unusual activity.

The devices go on sale today through Wyze’s mobile app — considering the system requires the Wyze Cam, the company is targeting existing customers right now. Wyze Sense starts shipping on May 7th, the company says.