The DL-BKIT2U-S optical delay line kit is configured as a double pass design ultizing the UBBR-2.5-5S retroreflector assembly with Newport's 10D620ER.2 ValuMaxTM silver mirrors mounted in ULTIMATM clear edge mirror mounts. To insure maximum compatibility to Newport's motion stages, all mechanical parts in this kit are metric compatible. All screws, clamps, posts, post extensions for mounting are also included in the kit. Please purchase the motion stage and controller separately.