Check the listing for details. Thorlabs M617L3-C4 617nm Collimated LED Light Source Module. Condition: Used. Listed at 120.00 USD. 60 Day 100% money back guarantee. Thorlabs M617L3-C4 is a mounted, collimated 617 nm LED light source designed for precision illumination in microscopy, machine vision, and general photonics work. This listing is for the module only and ships as pictured: no spacers, no lens accessories, and no power supply are included. Expect normal cosmetic signs from prior lab use. Electrical testing was not performed, so please review the photos closely to confirm fit with your setup. An external constant-current LED driver is required for operation. Great choice for rigid optical benches where stable, narrowband red illumination is needed. Keyword Block: thorlabs, m617l3, 617nm, led, collimated, optics, microscopy, machine vision, illumination, light source, photonics, lab