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.
It's to early to tell if the are going to keep the rooms any cooler but I really don't see how they will not. Before I installed them I placed one above my head in the hot sun and it felt as if I gone under a tent. I bought two and immediately bought three more for the front of my house because I like the way they look.