The VooPoo UFORCE U4 Coils are engineered for compatibility with the UFORCE Sub-Ohm Tank and UFORCE T1 Sub-Ohm Tank systems. These coils utilise a dual vertical coil structure and are crafted with organic cotton, ensuring optimal vapour production. They are rated at 0.23 Ohm and are suitable for use between 50 to 120W, with best performance achieved at 60 to 80W.