1- Project Box 3x2x1. UPDATE: scratch this. Use a bigger one! The pins from the switch didn't fit inside so I had to mount it the wrong way, and the battery didn't even fit! I would suggest using one at least a 1/2 inch bigger on all sides.
3- Velcro Straps or Hose Clamps - you could use zip ties, but then you would have to cut them every time you needed to remove the turn signal system for transportation.
1- Project Box 5x2.5x2
2- 10 ohm resistors
1- 9V battery snap
1- Center Off 3-way toggle switch
10- 5mm Yellow Flashing LEDs. Get some that require 1.8V so that you can use a 9V battery.
10- 5mm LED holders
2- old bike reflector mounts (one rear mount and one front mount)
1- 9V battery
Hot glue or super glue
Drill with assorted bits
Solder & Soldering iron