Used Nikon TC-201 2x Teleconverter

Glass is clean, no haze or scratches, and it locks onto my 300mm f/4 with a satisfying click. The 100-day warranty gave me peace of mind buying used, but honestly the body feels solid enough that I doubt I'll need it. Sharpness drops a bit at the long end but that's physics, not this unit's fault.

Even with my older Nikon lenses, the autofocus is still snappy and the image quality holds up surprisingly well—definitely sharper than I expected from a 2x converter. The included body and rear caps were a nice bonus, and the lens itself looks barely used.

The included caps and 100-day warranty gave me peace of mind for a used item, and the optics are tack sharp with my 300mm. Lost half a stop of light, but that’s expected with a 2x converter.