Heavy-Duty Utility Blades fit all standard, heavy-duty, and retractable blade utility knives. This style blade is available in 10 per pack and in a bulk 100 pack dispenser.
Screens appear to be good quality material and sturdy. I was worried that one or more might not fit, but they all did, so my measurements must have been correct and you made the correct “cuts.” Somewhat challenging to unpack the screens but packing is very secure to protect against bending during shipping. I accidentally dropped one screen on another one while unpacking them, and, I unfortunately put a small hole in one screen. Is there a repair kit available?