The official Nintendo website has posted the technical details of the Nintendo Switch, including the dock and the Joy-Cons.

We now know that the console measures 102x239x13,9mm with the Joy-Cons attached. The weight of the console is only 297 grams; 398  when you attach the Joy-Cons.

The CPU/GPU however is still listed as "NVIDIA customised Tegra processor". The mention of a headphone .mic jack gives the idea that we may expect a headset with microphone options.

Supported wireless options are wi-fi ac (which is faster than the b/g/n which is still standard in many devices) and Bluetooth 4.1. 

The battery is a 4130 mAh lithium-ion battery, which lasts between 2,5 and 6 hours and takes 3 hours to charge. Nintendo already made a statement that the battery is not replaceable, however they will offer a (paid) service for replacing it if necessary.

All details can be found here.