Seco Double Right Angle Prism (Penta Prism) The Seco 4900-00 Double Right Angle Prism is a compact optical tool designed for quickly establishing perpendicular (90°) alignment between two points . Ideal for layout, construction, and basic surveying tasks, it allows users to easily determine right angles without the need for complex instruments. Key Features • Designed for establishing right angles (90°) • Enables quick perpendicular point layout • Compact and easy to use in the field • Ideal for construction, layout, and basic surveying applications