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sigelei 75w tc can also do nickel builds. Just like noodle said. I use the same coil set up in my tugboat rda with kanthal and it's great at 40w-45w-50w. Only down side is the sigelei 75w is a single 18650 so it will tear through battery life at those wattages. Still a nice vape though and it's not a big deal if you have a few 18650's to rotate to the charger and mod.
As far as nickel builds I have yet to really attempt a nickel build in my rda. If I do it will probably just be a single coil build rather than dual. Nickel has a crazy low resistance and I don't want to over work my battery.