Like any other filter, this one protects the front lens from water splashes. 

Please check sub-table 2 for the operators corresponding to different countries, please update the operation according to your site. For example Germany is: T-Mobile, Vodafone, E-Plus E-+ Mobilfunk 

1.I’m sure it’s glass - when I clean mine with isopropyl alcohol they make that ‘squeaky’ noise you get with glass rather than plastic, and they’re more resistant to scratches than most plastics are. According to manufacturer website K & F use German optical quality glass so I’m sure they would have been called out for that a while ago if it wasn’t true 2.I drop one last year and it broke like glass ..I’ve found them easy to clean and well made. 3.Looks and sounds like glass to me 4.HD optical glass 5.As far as I can tell it is glass. Excellent optical qualities 

I have used one on a Sony a7 mkii. 

You could try this tip. Hope it helps. Pan&tilt operation: Press the “pan/tilt” button on the upper right corner (A direction icon will appear in the middle of the screen when you press the “pan/tilt” button) →use the sound and brightness buttons to move the lens(The specific operation is shown in the video).