Vaporesso Ceramic EUC (ECO Universal coil) with Sleeve, a new game changer to vaping, is designed to deliver cloud vapor with the purest flavor. The EUC will allow you to replace only the core of your atomizer which is called EUC by dropping it in and out of its casing, leaving the metal sleeve. It can be used with Estoc Tank/Target Pro/ ORC/ Gemini Tank. 10pcs each pack with 1pc sleeve or 5pcs without sleeve. Get it as spare parts.