For general construction squaring (framing, decks, paving stones, etc.), a large A-frame square is handy.
Not only does the third arm make it easier to use, but the extra length (double the arm length of a standard square) makes it a practical substitute in the more time-consuming process of measuring diagonals. Equally useful, this 3' × 4' × 5' aluminum square folds to a slim 5' × 2" × 3/8" for travel or storage.
An excellent layout tool, it weighs only 3 1/2 lb and is accurate to 1/32" over 4'.
Made in USA.