So after buying and trying several tanks I finally found an rta that my wife has used leak-free, the Sapor RTA. Everything we have tried up to this point has leaked to some degree with the only juice she vapes which is a simple menthol. She is so happy with the Sapor she wants a second one and I just found the bigger 25mm Sapor RTA as well as the OBS engine. Im wondering if the Engine is just as good and is as leak-free as the Sapor,plus its cheaper. Thanks for any and all help and Vape On!