The Spare Silicone Crystal with Holder comes standard with the Micro ATR Objective Upgrade Kit (L1860334). With this part number, this crystal can be ordered separately as a replacement or spare.
The Micro ATR Objective Upgrade Kit upgrades Spotlight 400, Spotlight 200i, Spotlight 100i, and microscope systems without an ATR capibility with a micro ATR facility that covers the range 5,500 – 600 cm-1.