The Zona L-Square aids in building straight and true and it has imperial measurements on one side and metric markings on the other. This tool will help ensure that your rib angles and fuselage sides are straight. And don't eyeball whether your fin is perpendicular to your stabilizer - use this L-Square to check!
It is easy to handle on your workbench, due to its convenient 3″ x 4″ size. Zona part #37-434. Made in the USA.