Keep your Terp Pen XL running like new by replacing the coil every few months. Depending on your usage, we recommend disassembling the Terp Pen XL once per week and wiping down the internals with isopropyl alcohol. Let air dry after cleaning and perform a burn-off (instructions included) prior to use. Boundless Terp Pen XL coils are made up of high-quality ceramic which is wrapped with a medical-grade stainless steel wire. The coil is instantaneously heated when the breath sensor is activated, allowing for you to dip the coil into the concentrate of your choice and enjoy.