Thorlabs MB1224, Optical Breadboard And Optical MountCondition:* Used, Sold As-Is. As Pictured. Additional Notes:* 1/2″ (12.7 mm) Thick* Standard Imperial and Metric Breadboard Hole Patterns* Offset Mounting Counterbores Allow a Full, Uninterrupted, Threaded Hole Matrix* Black Anodized Surface with Low Reflectance* Flatness: 0.006″ over 1 ft* Hole Size and Spacing: 1/4″-20 Tapped Holes on 1″ Centers* Distance from Edge to First Hole: 0.5″ on All Sides* Number of Counterbored Holes: Four 1/4″-20 Located at Corners – Inset 1″Thorlabs MB1224