From GROK

Thorlabs VB01 is a vertical bracket for mounting optical breadboards. It's an 11.75-inch tall, black anodized aluminum bracket designed to securely hold aluminum breadboards in a vertical orientation on an optical table or breadboard surface. The triangular shape provides rigidity, the central cutout reduces weight while maintaining strength, and the base features a row of 1/4"-20 clearance holes spaced at standard 1-inch intervals for flexible mounting alignment with optical table hole patterns.  1/4-20 thread pattern.