This wrench is designed to reach up behind a sink. The compatible nut size goes from approximately 1-3/8 inch to 5/8 inch.

The extrnsion handle is a press fit with a 0.175 design offset. It seems to work out nicely.  To reverse the rotation, remove the jaws and invert it before replacing it on the shaft  

The back spring is 0.8 mm thick.