300MM LONG: For marking out and measuring detailed precison cuts on site, at home and in the workshop. VERNIER DEPTH GAUGE, METRIC AND IMPERIAL: Built-in vernier depth gauge for measuring rebates, housings and mortise depths. The scale is reversible, so you can read millimetres or inches from the same edge without a second ruler. ALUMINIUM ALLOY BUILD: Machined body and blade - light enough to carry all day, solid enough to hold a true edge, and it will not rust in a damp workshop. 45° AND 90° IN ONE TOOL: Mark and check both square and 45 degree angles without swapping tools. SLIDING HEAD THAT LOCKS: The head slides along the body and locks at any point, so you can set a distance / depth and scribe the same line down the full length of a board without measuring again.