SLAC National Accelerator Laboratory is requesting quotes for one single-crystal silicon FZSi monochromator (220), with specific dimensional, crystallographic-orientation, edge-polishing, surface roughness (=5 nm RMS), flatness (=100 nm RMS), etching, and marking requirements, along with explicit technical compliance documentation. Award will be based on lowest price and best lead time, with the resulting purchase order on a fixed-price basis under SLAC’s standard terms. The Buy American Act certification applies to awards over $15,000 unit price, and subcontractors must be registered in SAM. This is a product-only requirement with no on-site services; delivery is to SLAC National Accelerator Laboratory in Menlo Park, CA, with domestic FOB destination prepaid and add terms.