Cart battery that looks and works as a real pen! Amazing two in one! Comes with the charger. more info at the SMYLE website: https://smylelabs.com/products/smyle-labs-pen?srsltid=AfmBOooI_k7eY3rvHzEpvbuzHIl3e80KEC-nGoDxS6_7k1Cebrk64D2a