The Smoktech RDA (Octopus) is a rebuildable dripping atomizer made exclusively for dripping in mind. The RDA comes equipped with a removable anodized top cover with 2 orings on the base to keep it in place and can be used with 510/901 drip tips. Native 510 threading. The RDA comes standard with a 1.7ohm pre-wrapped coil. The positive & negative posts are knurled to make remove the coil and wick easy and painless without the use of screwdrivers. As the bottom connection is sealed, it will not work for bottom feeder mods and should used strictly for dripping.