Quantity   Component name
1 × LED flahslight I used the Harbor Freight 27 LED flashlight
1 × 1K Ohm resistor provides 1K Ohms of resistance
2 × 100k Ohm resistor provides 100K Ohms of resistance
2 × 1 uf capacitor I've found that this capacitence provides the best flash rate. Higher ones provide a slower flash rate, and lower ones tend to make the system unstable.
1 × 47 uf capacitor this capacitor is used to control the off period
2 × 2N3904 transistor Your basic NPN transistor
1 × 100K Ohm Potentiomiter this is used to control the off period
1 × 2n3906 transistor your basic PNP transistor