Saker Miter Saw Protractor|7-Inch Aluminum Protractor Angle Finder Featuring Precision Laser-Inside & Outside Miter Angle Finder for Carpenters, Plumbers and All Building Trades (Black) : Amazon.co.uk: DIY & Tools
Starrett 505P-7 Angle Measurer - Screwfix
NTD: no more crappy mitre cuts for trim work : r/Tools