I am confused by the multitude of parts that appear to be the same but have different part numbers.
For example, I can find 4 Shimano XT V-Brake Levers, and I can't see the difference between them.
BL M739, BL M740, BL M770, and BL M771 are all Shimano XT V-Brake Levers.
Or for Shimano XT Hubs for rim brakes, I can't see the difference between the 760's and the 770's.
To make it all a little more complicated, the manufacturer's Specs for my bike simply say XT V-Brake Levers... the number BL M739, etc are not specified. The Specs don't specify the part number for any of the parts.
How do I figure out which replacement parts to order? Or which part I currently have?