The 12" folding layout asquare is great for unter tops, non marring mposition, timber, masonry, pavers and much, much more. The 3' x 4' x 5' heavy duty aluminum 90°folding layout uses: Carpentry, layout, angle layout, squaring, framing timber, masonry, pavers and much more. The 3' x 4' x 5' is accurate to within 1/32".