I thought you might like to see a change that I make to my Tom Bihns. I like to color coordinate the zipper pulls to match the color of the bag.
This bag is Black/black/cayenne so I found some black and red nylon cord boot/shoe laces and used them to make new zipper pulls. You can use any nylon round cord that is 1/8" or 3/32" diameter. Just take the originals apart and use the black cord as a guide for the length. Use a lighter to melt the ends of the cut pieces so they won't fray.
There are dozens of colors of this cord on the web. Just search "boot laces" or "nylon cord".
Just adds a little color and makes it easier to see the zippers when there is low light in the room