Guys I've recently needed to make some lines with double flares. Went through all kinds of trouble and figured Id share it here to maybe help somebody else out. I started with essentially this one from NAPA: http://www.napaonline.com/napa/en/p/BK_7769167 Not identical but very close. That worked for the NiCopp (nickel copper) line which is soft, 3/16 I had. From there I needed a 5/16 fuel line and its regular steel. Well that would not stay clamped, and it ate up the teeth in a hurry. I returned to NAPA and upgraded to this: http://www.napaonline.com/napa/en/p/SER41860 The Yolk or C clamp, whatever you want to call it would sit cockeyed......messing up the flare. The 5/16 steel slid through still, and ate up the teeth in the clamp........even though they claim the tool is hardened steel. I asked some guys on Garage Journal and we came to the conclusion that the Cal Van 165 inline flare tool is one of the better units without spending 200 bucks on an eastman hydraulic one. Well being that the Napa guy has been cool and helping me I wanted to see if they offered one like it. They do, its identical in every way to the Cal Van, except twice the price. I asked if he'd match it, which he reluctantly did - mainly because Id gone through 2 of the other tools. The Cal Van is a different design with a sheath that screws over the die, which locks it in and makes it clamp down straight. I thought this was fool proof but sure enough the 5/16 regular steel line chewed up the teeth on the Cal Van too! It just slid through and did nothing. I called up my guy at Napa and at this point (this has been over the course of a week), he was over and done with it and advised to ditch the steel line and he'd order some 5/16 NiCopp. Thats all well and good except my tool had chewed up teeth now, rendering it unfunctional. So I called Cal Van directly. The lady asked me what color the clamps were. I said silver. She informed me they've been having trouble with those, and they now make them out of hardened steel. She took my address and is sending me all new clamps. I'm excited to see the difference. Also happy because the machining on the previous ones weren't the cleanest (some turned easy some not so much). So thats where I stand! On a side note the Napa guy informed me that the NiCopp line is safe for fuel, brakes, trans cooler, etc. So that is souly what I'll use from now on. Not sure why plain old steel is so incredibly difficult and its eating up tools. I guess its because they're all made in China or Taiwann maybe. Outside of that the Cal Van tool seems to be a quality tool, superior to the common style and hopefully the hardened clamps will make it up to the task.