Antimicrobial High-Pressure 6-setting Hand Shower

I have never installed a shower head before but this was thankfully easy to do. I removed my old one easily as well. No tools needed. It's lightweight and flexible hose compared to my old one. First try there was leaking at the top so I tightened it and it was ok second try. I was worried to tighten it. I haven't tried all the six settings or showered with it yet so I cannot fully review. My only complaint so far is the tilting angle of it. My old one I can tilt it downwards more. Hopefully it wouldn't matter too much when I shower. Our old one we had for around 16 years and it is gross with black/green and some pink mold. I don't know why we didn't notice or replaced it sooner!By the way, we live in a condo and our shower always had decent water pressure. It doesn't seem this shower head affected or limited it. I chose this shower head mainly because it is anti-microbial. I hope it lives up to its claims!I will include images of what was included in the box and what is this yellow thing? Glue? Sorry, I'm no expert but I didn't use it.-----------------------------UPDATE 4/18/2019So it has been two years now since we purchased this. It's still working and in good condition. Slight leak but that's my fault for not installing properly. There's a very minor rust in one small area around the blue rubber. I assume that's rust because of the color. For two years I think it's doing pretty good!--------------UPDATE Jan 18, 2020The time has come.. the mold is here. I'm not sure of the exact date of when it started but it's more obvious recently. We are headed into 3 years since purchase. I don't think we are supposed to keep a showerhead that long so I still think this is decent product, however, we only like 1 out of 6 spray patterns.