Flash Filter Stack Set.

WARNING: Ultraviolet and Infrared light can be dangerous. Always wear suitable UV and/or IR blocking eye protection and skin protection when using UV and/or IR illumination.
This set of filters transmits invisible UV radiation (light), and should not be used around people, animals, or anything that may be sensitive to UV/IR unless proper protection is used.

ATTENTION: Filters ONLY! Speedlite 199A is NOT included in this sale (NO FLASH included).
Intended for use with Canon Speedlite 199A Flash, to replace front plastic lens.
Two filters:
Hoya U-340 35.5mm x 59.8mm x 2mm thick.
Schott S8612 35.5mm x 59.8mm x 1.5mm thick (2mm thick also available).
It is up to you to make sure these dimensions will fit and work for your specific flash or application. These may not fit all such flash units the same way, so measure your flash first.

Here is a YouTube video by Evan at Photoextremist.com showing the use of these 199A UV-only flash filters for UVIVF (fluorescence) photography:
YouTube Video

These filters are quality made from genuine Hoya U-340 and Schott S8612 optically polished filter glass. Precision crafted size, thickness, and edges. Freshly made from new glass. Cut and mounted in the USA.
(Schott and Hoya filter glass is the very best premium quality filter glass in the world. If you want a quality filter then get one that is made of Schott or Hoya filter glass)

NOTE:  With filter glass types S8612, BG39, UG5, and UG11 a change in the glass surface is possible overtime.
I have experienced no surface problems with these glasses myself, however, climate, humidity, and other factors vary substantially so you may experience different results.
In humid regions this glass may show signs of surface oxidation sooner, therefore I recommend storing these 4 types of filter glass with desiccant in a sealed container at all times when not in use.
Cladding can diminish UV transmission, so I use these types of glass in photography non-clad and non-coated.
However, some surface oxidation can develop over time, thus S8612, BG39, UG5, and UG11 glass may need to be re-polished eventually, and is not something I currently provide.
Schott BG40 (and BG38) is more durable glass and may be a viable substitute for your application (when thicker than S8612), but having less UV transmission and less IR suppression than S8612.

Glass:  Hoya U-340 and Schott S8612
Filter thread size:  each are 34.5mm x 59.8mm rectangles.
Glass thickness:   U-340 = 2mm thick, and S8612 = 1.5mm thick. (custom thickness)
Color:  U-340 is black/opaque, and S8612 is light blue green.
Type:  UV-Only filter stack set for Speedlite 199A flash.
Range:  320nm - 400nm transmission (see graph above)
Used for:  UV flash

This was designed for my Speedlite 199A, it may also work for yours. Fits inside the removable front diffuser frame (you must also remove the clear plastic from inside the flash body, be careful with that).
If you need something specific, message me to inquire about listing any type of Schott or Hoya filter glass, in any size, any shape, or any thickness (price, availability, time, details).

I am happy to make this and other hard to find specialty filters, sizes, thicknesses, and shapes available to you on request.
Feel free to message me if you have any questions or requests. Please let me know if you find any errors in my listings.
Thank you!