These Fire handle lenses are created from 3mm frosted red acyrilic. Laser engraved and filled with white wax. The excess wax is then removed, and a clear lacquer is applied for protection.
 
The price is for a set of 3. 
 
The dimensions are 21mm +/-1 wide x 50mm +/-1mm high. (3mm thick)
 
The lenses are designed so that they can be backlit. A cheaper DIY version is available without the wax infill to keep costs down.