Looking for a wireless doorbell type device, to be used as a remote security call button. Ringer powered by batteries or plugs into mains socket, no wires. Wireless between transmitter/receiver for ease of installation, able to work through one wall at a distance of approximately 15-20 feet. Must have a ringing or buzzing sound that cuts out when the button is released, no annoying chimes that go on for ages. Loud enough so it can be heard over disco music by someone standing 2-3 feet away from the bell/buzzer.
Can anyone recommend a specific product that can be purchased in shops, not off the Internet. Cost is not really an issue, as I'm not paying for it out of my own pocket, so not looking for cheap and nasty, but obviously the person paying for it isn't going to pay silly prices.
Marcus