Made by Boge.. These are a great addition to allow extended use of your 510. The little rubber stopper on top pops right out with a paperclip or other small object for easy filling. Holds 20 or more drops of e-liquid.. These are empty, safety wrapped and brand new.. Approximately 36mm long (1.5 inches). Resistance is approximately 2.0 ohms. These produce a great amount of vapor without killing flavor!