SvoëMesto Kayfun 5² - PEI (ULTEM) Tank Kit
The optional PEI Tank Kit for the K25 is cool modification that allows you to monitor your e-liquid level without losing the aesthetics of the steel tank. The kit includes a matching Drip Tip made of the same robust thermoplastic material (polyetherimide), also known as "Ultem".
The max. fill volume is 6 ml with this tank.