This 2 pack of herbal atomizers is designed to seamlessly work with any 510-threaded battery, making it easy to enjoy your herbs on the go. Retail Unit: One (1) Pack. Each pack contains two (2) Herbal Atomizers Size: 52.3mm x 14mm Voltage Range: 3.2V to 4.2V Chamber Capacity: up to 18mm Heating: Stainless Steel Thread: 510