The Uwell Crown 2 replacement coils are specifically for the Uwell Crown 2 Sub-Ohm Tank. Uwell has redesigned their coil Crown coils to be more efficient and have a longer lifespan. The coil design features larger juice ports, this would improve the wicking process, allowing you to chain vape and push to a higher wattage.

Uwell - Caliburn A2/AK2 Pods 

Pack of 4 empty refillable replacement pods for the Caliburn A2/AK2