Totally agreed, just in this case I have had 2 different eVic's and neither have the nice precision machined fit that I get with my zMax. I returned the first to the vendor for loose threads and the 2nd one was better but still not even close to the zMax. Don't get me wrong, I LOVE the variable wattage profile that I have built and can't see switching to another device, just not happy with the 510 threading.