Smoke detectors should be heard (when appropriate) but not seen. Usually, they are both. The FCP-500, however, adds a certain level of stealth to a product that generally has none. Designed for architectural applications where aesthetics are important, the unit has a smooth, flush-mounted surface that blends in with the ceiling and a faceplate that can be painted. The cover comes in off-white and clear. Cost: starting at $300. Bosch Security Systems. 800-289-0096.