Used Nikon TC-201 2x Teleconverter

Even though it's used, the glass is spotless and the metal mount clicks on tighter than some brand new gear I've owned. The 100-day warranty gives me peace of mind for a secondhand purchase, and the included caps mean I could throw it in my bag right away.

Put this on my D500 with a 300mm f/4 and the autofocus stays snappy, even in lower light. The glass is clean and the mount feels tight—no play at all. Exactly what I needed for a bit more reach without dropping a ton of cash.

Picked this up as a used Nikon TC-201 2x teleconverter and was pleasantly surprised by how clean the glass and body are given its age. The included body cap and rear cap were a nice touch, and having a 100-day warranty gave me extra confidence in the purchase. Tack-sharp with my 300mm f/4, no regret