Feel the HUM with optional Haptic feedback as you inhale. Always have the power you need! Features: 2x active cartridge ports Aluminum housing with a steel base 550 mAh battery capacity Inhale activation Subtle LED indicator Optional Haptic (vibration) on inhale Ergonomic shape 3x Magnetic 510 screw-on adapters 50mm braided rope Micro USB cable Compatible with bottom airflow 510 cartridges