Check the listing for details. 4.5 in. 90-Degree Precision Squares & Setup Blocks, Laser-Etched Scales. Condition: New. Listed at 28.53 USD. These versatile, durable squares are made of CNC-machined aluminum, then anodized and engraved with laser-etched scales. Each square features multiple clamping holes to maximize versatility and make positioning and setup easy, whether on the inside or outside of your workpieces.