Not sure if I got a defective item. I bought this item specifically to power my Raspberry Pi that recommended a 2.1 amp power source. This charger states 2.1 amp, but when I use it w/ my Raspberry Pi, my Pi says it is under powered (giving the colored square icon on the upper right hand corner). What a disappointment.
I bought 3 of these to use with various USB devices. They are about the size of a heavy 3 prong US style AC plug. The devices I use them on prefer a 2 amp charger which is why I bought these. They work as expected and do not get hot. I believe the size helps to dissipate the heat. Highly recommended!