Seco Contractor Series Tribrach with Twist Focus Optical Plummet The Seco 2152-04-BLK Optical Plummet Tribrach features a twist-focus optical plummet (2.5X magnification) for precise centering over control points in surveying and construction applications. Designed for accuracy and durability, it includes smooth three-screw leveling with center lines and a standard forced-centering base for repeatable instrument setup. Key Features • Optical plummet with twist focus (2.5X magnification) • Focusing range: 1.5–50 ft (0.5–15 m) • Three-screw leveling with center line alignment • 8-minute circular vial for accurate leveling • Standard three-prong forced centering • 5/8” x 11 base thread • Durable construction for field use , not suitable for Trimble S Series Total Stations