The charger itself is quite slim that 40W is sufficient for me also completely. Ultrabook (Samsung 740U3E) is very well loaded. In addition, the charger has a bright blue LED that indicates when power is available. For me, unfortunately, some bad and in my opinion in need of improvement: The 230V plug is round and interfere in my Ultrabook Bag (Cool Bananas RainSuit Stripes neoprene sleeve) a little. If this man were flat, the minor would not be in my pocket so build. Nevertheless, good charger. Can I recommend.