Little things like this are easy to lose (if they even came with your bike), but they can save the day when you’ve gotta remove the wheels to travel with your bike. One accidental squeeze of the levers and you’ve gotta find something to pry the pads apart enough to get your rotor back in place. While a flat head can do the job, it could also damage the pads, so better to avoid the issue in the first place by simply inserting something that’s better looking than a scrap piece of corrugated cardboard (which also works, BTW, but only as preventative maintenance). Thingiverse has you covered with the plans to print your own, you just need a 3D printer (or a friend or makerspace with one).
