Try Square Bahco 9045-B-250, 170 × 250 mm

A precise square especially for carpenters, ideal for marking, checking, and adjusting right angles. The square fits evenly against the end of the board and is made from a single piece. Designed for precise measurements at both 45° and 90° angles.
– Aluminium rail on the back.
– Clear measuring scale on both sides, on the outside and inside.
– Phosphated, coated with a rust-resistant finish.