How to make your own red "lens".

For using the Mini Maglite AA and similar flashlights as a bicycle tail-light .

Materials :

- A piece of thin and soft red plastic
 ( I have used red plastic from a ketchup bottle )
  size : 10 x 5 cm (4 x 2 inch)

- A rubber band
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1.
Cut like this.

Cutting template
(Pdf, 5 Kb) 

2.
Fold and place the rubber band.

3.
Place like this on the flashlight.

4.
Result :
A very good tail-light with
good visibility from all sides.