The Bubble strip on your lightsaber.
The general consensus is that the part where the bubble are on the lightsaber handle the bubble strip would come from old Texas Instruments calculators. These are hard to obtain and fetch high prices on auction sites since they are highly sought after for lightsabers constructions.
The flash gun has a mounting clamp in the middle that attached to a camera. To achieve the on screen look you have to slide into this clamp a Light Emitting Diode display bubble type lens that came from a vintage calculator.
The Following models had the appropriate number of bubbles tobe screen accurate:
These calculators were made by Texas Instruments.
You need to break the calculator appart in order to get to this part.
The Exactra 19
Some people have reported that they have used a Mister wizard Calculator to get the bubbles that they needed. But it would require a lot of work to modify the strip to look right and would be innacurate to the screen used bubble strip.
The bubble strip has to be set up this way.