This is an optional accessory of a laser autocollimator.
LAC-PP can be properly bend the optical axis 90 °. If you want to measure the squareness of two surfaces, is used as (Optical square) criteria of squareness.

※LAC-PP is Nikon Instech Co., Ltd. will be the distributor.
Please contact Nikon Co., Ltd. for the RoHS Directive.