The Seco 6405-10 is a durable compact mini prism that features ‘site cones’ that improve vertical angle pointing.
The site cones also double as tilting-axis lock knobs.
The adjustable 40-min vial is mounted on the front side of the unit and is easy to see and simple to adjust.
This mini-prism is also a zero-offset if you reverse the prism from it's standard 30mm offset.