With the Mitutoyo 900372 extension base, you significantly improve stability and accuracy during depth measurements across wide openings. When inspecting large bores, slots, or cavities, this accessory prevents your depth gage from tilting or rocking. Featuring an extended span of 320 mm and a width of 8 mm, it provides a solid, balanced reference surface on your workpiece. You can fasten it directly to the reference face of compatible Mitutoyo depth gages with a measuring range up to 300 mm. This gives you dependable, repeatable precision for quality control, metalworking, and machine workshop tasks.