Hyperbola Collection Bangle

Is this covered by the Swarovski 2 year warranty like you get when you buy from the shop?

Does this metal tarnish or fade over time. Ove only ever had white gold ao this is new to ke. How do u clean the bangle?

The bracelet comes in 3 sizes, but not clear how to which size would fit. There is a size in the description like 5.4 x 4.8 cm, what does this mean?

The size of the Large is 19.5 cm please can you tell me the size of the medium bracelet