Feather Double Edge Blades, 10 Count

I don't really understand, how many are there in the 10 count?

I Just found my Grandfather's Gold plated Gillette tech razor and I thought I might switch over to it. Is there one blade which will work best?

Why are these in a black and gray packaging? Feather razors usually come in a yellow packaging and they usually don't ship from Thailand. Fakes?

Why do your blades come covered in adhesive?