I fitted my Light 15 with a “high level” LED brake light. It is attached to the bottom of the rear window and is only about 1/4″ wide so pretty unobstrusive. There are some on the market that are even narrower than that. Tapped into the rear brake feed and all wiring hidden out of the way when I reupholstered. At least everyone can now see me braking even if I think nothing is happening when I push down on the peddle!