Here is a tail light I made awhile back. It is made from an old brass boiler valve. It measures 2 1/4" long, the body is 1 1/2" in diameter, the face ring is 1 3/4". Red acrylic lens. It has a Radiantz 1.25" 25 red LED puck and is setup for hard wiring. The mounting stem is threaded 3/8 x 24NF with a custom made stainless steel mounting nut. The housing and nut are raw but you can easily polish it if thats the look you want. The first $90.00 takes it.