The Dewalt 18cm and 30cm Metric Speed Squares should be a part of your tool kit.
The large fixed base ensures a better grip on materials while the stamped in contrasting colour graduations delivers clarity when reading the measurements.
The extra-thick, extruded aluminium body is perfect for heavy duty work and as use as a saw guide.  The pivot point makes marking angles easier while the scribe line notches allow for marking for rip cuts.
The scales of top cuts of common jack rafters, hip and valley rafters for versatility