Review on Johnson Level Tool Structo Cast Sliding: A Premium and Reliable Precision Measuring Instrument by Mike Rajput

Somewhere between $2 and $3, the value certainly can't be beat. It's quite a substantial weight so you don't feel like it's about to break. The only reason you'll likely need something better is for accuracy. There is no marking so you just copy the corners and don't install new ones. It does get the job done though - solid 4 stars.