Here's what people who bought this item say:

On February 21, 2024 ebay user ke5o-steve wrote:

"Great item!!! Quick ship!!! Thanks!!!"

Microscope Camera 5 mm C-Mount Ring Extender (USA Shipper).

Use this adapter to extend the distance of your microscope-mounted camera.  It's made from aluminum and may be stacked to increase the distance as needed.