"Honeywell FFS switches are designed to be tamper-proof, standalone safety switches that can often be used to switch relays, contacts, or safety relays directly. By removing the separate control unit, Honeywell has made it possible to use its electronic switching technology in smaller, simpler safety systems. The FFS is often suitable for use on its own, for lower category safety systems, providing two volt-free outputs (2NC or 1NC\/1NO). It can be used in conjunction with safety relays where a higher category of performance is required. For ease of operation, the fixed switch has a green LED, giving true indication of FFS safety switch contacts."