The Topeak Nano TorqBit is a 1/4″ hex bit with a fixed preset torque value that you can use with each bit holder and each bit. I personally use it in combination with the Fix It Sticks T-Way wrench that I reviewed a little while ago, but it also comes in a set called the Topeak Nano TorqBar.
I will also compare the Topeak Nano TorqBit against the Ritchey Torque Key which also has a fixed preset torque value.