The “Core Series” Glass Twist-On 1.0ml Cartridges are designed to deliver the best experience with either thicker or thinner oils. Made from quartz glass, the construction is very appealing and says “quality” at a good price point. The BPA free glass tank is designed to withstand drops and breakage from heavy use. The closure/ mouthpiece at the top of the cartridge is twist-on, enabling a quick and customizable change of sizes and shapes. Designed with a porous ceramic core that heats evenly and is long lasting, the Core Series Twist-on is optimal for everyday vaping use. With a universal 510-thread base, Core Series Cartridges pair well with any standard battery. Every component has been chosen to provide a safe, and enjoyably smooth vaping experience. Included is a base mouthpiece with a choice of either Black Twist-on ceramic or White Twist-on ceramic Duckbill shape.