These replacement atomizer heads are designed for the Joyetech eGo ONE clearomizer and the Joyetech eGo ONE XL clearomizer. The eGo ONE works with two types of atomizer heads. The 1-ohm atomizer is intended for mouth inhalers as it mimics the feeling of taking a puff. With a tighter draw, it is perfect for people who want to enjoy the same sensation as smoking a real cigarette. The 0.5 sub-ohm atomizer is designed for users who want an effortless draw as they chase huge clouds of vapor that go straight into the lungs.