I have two Nasco fixed torque drivers: a 22"lb and a 40"lb. These two cover most of my needs, the smaller 22 for tightening scope rings and the 40 for attaching rings to bases and torqueing receiver action screws. The drivers seem well made and even have a piece of paper certifying their accuracy. I suppose over time, the settings can gradually change and thus benefit from recalibration, but I haven't bothered to do so.

I also own an adjustable torque driver from Northern Tool. It seems to work OK, but I can't speak to its accuracy or repeatability.

I was hoarding when hoarding wasn't cool.