Another option would be a Lutron Pico remote, assuming you have a Lutron Caseta or RadioRA2 lighting system already. Lutron even makes an automobile visor clip for the Pico remote.
If you only need one button device, investing in a Lutron system is pretty expensive. However, Pico remotes can be bought for about $15 a piece in North America, and they have a 10 year battery life. Lutron also makes very reliable switches, dimmers, and fan controllers.
