Millions of Americans have been working from home since the coronavirus lockdowns began, but that’s not to say they’re working unobserved. According to published reports, demand for staff-monitoring services has surged since the beginning of March.

But how do these remote monitoring services work and what do they cost? New York-based information technology provider Atlas VPN recently conducted a survey of six popular platforms (Hubstaff, Workpuls, DeskTime, ActivTrak, EmpMonitor, and Teramind). It found that basic packages typically include screenshot captures, website-visit tracking, and productivity score calculation, which is measured by how often the employee types something in or moves the computer mouse, the company said. As for what these services cost employers, Atlas VPN found that the average fee for monitoring a single worker was just $7 a month.

The study apparently raised some concerns among Atlas VPN leaders. “Managers should look for better ways to ensure their employees are productive while maintaining respect for their privacy,” Rachel Welsh, COO of Atlas VPN, said in a release. “Some of the features these services include, such as keystroke monitoring, are too invasive. Not to mention, results from these systems show are not always accurate—employers should never fully rely on automatically generated reports.”