Don't underestimate the importance of a tool like the Unior Bike Brake Disc Spreader, also known as a pad spreader. Sure, you could shove a flathead screwdriver in there and gouge your pads while you're at it, not to mention force them apart unevenly. Or you can do it precisely and deliberately with Unior's rubber-handled, purpose-engineered wedge.
[blade] steel, [handle] double component rubber
installing/adjusting disc brake calipers