Kodak 3x3" (75mm) #47 Deep Blue Wratten Gel Filter

It's a gel filter

This is exactly what you would expect... a thin, gelatin filter that is extremely fragile. I wouldn't recommend any gelatin filter if it is going to be exposed to the elements... too fragile. Wratten filters are engineered with very high qc standards and are recognized as such by the fact that many scientific laboratories utilize Wratten filters for their optical equipment. If you have a need for a filter that passes or restricts specific frequencies, I would suggest purchasing a Kodak filter guidebook so you know exactly which filters will satisfy your needs, and then buying the corresponding Wratten filter. If you don't have such exacting needs, you may be better off going with a filter system such as Cokin, where they will be slightly more durable.