Help With Cancellation On Victorian Stamp

Hi guys!
I have started to sell of my collection of UK + commonwealth stamps.
In an 1942 album (I never really checked) from Germany, I came across this cancelled stamp.
One cancel says "LONDON & (...)" while the other says "UNITED STATES MAIL (...).

Can anyone help me with the story behind this + rarity/value?

Hi, Ralster, welcome to the forum. This is Scott 118 or Stanley Gibbons 207, the fivepence value from the Victoria Jubilee set of 1887, issued on the fiftieth anniversary year of Queen Victoria's reign and the first GB stamps issued in two colors. There is something to look for in this stamp and you will need a fairly good magnifying glass. This stamp was issued in two dies or types. You have to look at the little obelisk shaped value panel on the right which contains the 5d. Look at the tiny dots to the right of the "d" If they are square dots you have die 1, and if they are more like tiny vertical lines, you have die 2. Scott lists die 2 at $12.50 and die 1 at $125.00. Your stamp looks a bit faded. As for the cancellation, it was fairly common at this time on international mail for the receiving country to cancel the letter at the receiving post office. Not sure where this would have taken place on your example. As for rarity, not rare at all.

The United states cancel is an arrival / receiving mark. I believe 5d was the overseas rate for a 1oz standard letter from 1875 - 1907

Thank you both!

Highly appreciated :)