Sub-Ohm tanks and coils must be used by experienced and knowledgeable users as additional safety precautions must be practiced when using these items. These products need to work on a mod/battery capable of firing at sub-Ohm resistances. So, for example, if you have a 0.5 Ohm coil in your tank, your mod/battery must be capable of firing at 0.5 Ohm resistance, or lower. You also need to ensure your device can cope with the amps. Improper use can lead to physical injury and damaged equipment.