Genuine Asus VivoBook X512FB charger 65w, has the small micro connector with pin diameter 1.35mm, this charger power outputs at 19v 3.42a, this is an original Asus VivoBook 15 X512FB notebook charger and is the model which has the stylish square charging unit, which includes a clover power cable, some models of this series were supplied with a block charging unit which has a plug fitted directly to the charging brick, these are the exact same specification, the version pictured is most sort after, if you prefer the integral plug version or need the smaller 45w version, these can be found below.
Genuine Asus VivoBook X512FB charger 19v 3.42a specification
Power output: 19v 3.42a
Ac adapter power: 65w
Power input: 100-240v
Tip pin size: 4.0mm * 1.35mm (Asus new micro pin)
Asus charger p/n: VivoBook X512FB, PA-1650-78, 0A001-00441700, 0A001-00442900, 0A001-00043100, 0A001-00447800, 0A001-00046500, 0A001-00048600, 0A001-00049700, ADP-65, 0A001-00445400, 0A001-00449200, 0A001-00448600 and many more
Asus Ac adapter warranty: 12months
Contents: Genuine Asus VivoBook X512FB charger & Mains cable plug