If you're tired of replacing band saw blades too often, these Olson Cool Blocks might be your solution. They're made from this high-tech graphite-impregnated phenolic material that actually lubricates the blade as it runs - no oil needed! The big advantage over metal guide blocks is they run much cooler with less friction, which means your blades last way longer and you get cleaner cuts. These are the 12mm size (.472 inch) that fit most 14-inch, 16-inch, and 18-inch imported band saws. You get four blocks in the package, each about 3/4 inch long. Quick note - the blocks might measure slightly smaller than listed (like 0.45 inch instead of 0.472 inch) but that's intentional to allow for humidity expansion. Installation is straightforward if you're comfortable with band saw maintenance. They're made right here in the USA, and the quality shows. Once you switch to these, you'll notice the difference in cutting performance and blade life. Seriously one of those small upgrades that makes a big difference in your workshop.