Base Plate 3BP7R7 is designed for fastening 7R7 Mini Rotation Stages on optical tables and other surfaces. 7R7 Mini Rotation Stage is attached to 3BP7R7 Base Plate using M6 screws through 3 clearance holes on the base plate. Base plate can be attached to metric table tops using M6 screws through 2 clearance slots, or attached to imperial table tops using 1/4-20 screws through 1 of the clearance slots.