Pretty much every driver has had at least 1 near miss when it comes to backing out of somewhere. Sometimes it's a carelss pedestrian or a child on a bicycle, either way such situations are dangerous. Our Lady of the Trunk aims to help reduce the number of such occurrences.
The entire system is fairly simple requiring only 2 wires for installation. The speaker is attached inside the trunk and when the reverse gear is selected, a loud (and very assertive) feminine voice will precede your rear bumper with an announcement in the 100dB range. If you prefer a more traditional means of communicating your "R" gear, it can also be set to a loud "beep."
The whole kit costs less than $10.00 and includes the bracket, mounting hardware, 15 inch power leads and instructions in 3 different languages. Oddly enough, English is currently the only language available for Our Lady of the Trunk.
From : American Science and Surplus