I ordered an Oster #7F blade from Amazon, but the product’s quality seemed mediocre. The upper blade was catching as I tried to slide it back and forth. The upper and lower blades were also misaligned; however, the blade worked when mounted on the clipper.
I also ordered A new dual-speed Oster A5. It came with a nicely polished #10 blade. I’m not sure why the #7F blade’s quality was so poor.