I have several KF Lite Plus V2's, 3 kayfun 3.1's, 3 KF4's, and a KF 5. They are a mix of EHPro and Tobeco clones that work well. I vaped the 3.1 for a long time and then bought the Lite Plus V2's. The V2 airflow is more like a filter cigarette draw than the 3.1, IMO, and it's an easy fill from a thin spout juice bottle or a syringe. The KF4 was, as Maestro said, an over engineered failure.
