My absolute favorite, goes everywhere with me, is one from my nana, made of wood. It's styled like this. I love how I'm able to better grip it, and it stays in place. I am used to using flimsy cheap plastic ones which shift (you know the 6" ones that come with other art supplies?) Here it is: https://www.amazon.com/Architectural-Measurements-Laser-Etched-Triangular-Architects/dp/B07P5Q6835/ref=sr_1_1_sspa?dchild=1&keywords=architect+ruler&qid=1616064764&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyTENUTDBWNTlXWlRVJmVuY3J5cHRlZElkPUEwMjMxODI1MVhRRDc1SDlCMVAyNyZlbmNyeXB0ZWRBZElkPUEwMTA3NjcyMkQyS0g1REhLWUZWTSZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=