It has been sither too rainy or too hot out to actually USE the coupling hose, sl I can only rate it as far as I have handled it. Seems to be well made, as are all items I have made be Mr. Heater. I trust their products.
94 - 00 Volvo 850 S70 V70 XC70 Right + Left Rear Speakers 9128772 9128773 pair
Only one was sharp enough to mostly cut wood, all the rest were too dull to cut my own finger, and a couple had burrs that could be used as saws.
I do not believe they are 'high speed steel', and after I attempted to sharpen them, I have the impression that they need to be heat reated just to hold an edge.
Only two actually took an edge that allowed them to be used with the lathe... but barely.