Cordless tools been around a long time, though description has new connotation. Now batteries are commonplace, for centuries such tools ran on calories.
Here's one that I've had a long time, probably a garage sale find. Never seen another . But with little creativity it can be replicated. The best use is on automotive lug nuts. The function combines a free-spinning body when holding the bicycle-type grip, and torque tool utilizing the impact bar. Actuation is by gripping the handle and swinging the arm so lever directs power to the body and socket.
I suppose resulting power could be calculated, but it'll loosen those tightened by a pneumatic...When additional torque is needed just grab and rotate left or right by the end weights.
Click on the picture to enlarge view and read inserted text.
1/2" drive impact; cordless-cordless-impact-wrench.jpg
Any questions? Fire away, I'll be happy to respond.