Those work, but typically are set to a single value. You end up buying a lot of expensive T handle torque wrenches if you have mulitple torque values. Very useful if you use the same value frequently though.

For about $20.00 most could run down to harbor Freight and pick up a torque wrence that is accurate enough for propeller screw torque. Perfect? Absolutely not, but were not spec,ing to serious production standards that require annual or semi-annual certification of precision tools