This accessory allows mounting of a Nikon t-ring to Tak 35MM adapters to avoid vignetting. No t-ring included, but a Nikon t-ring from a camera shop will work just fine - that's what I was using. Sold my Nikon body so I don't need this anymore. Some wear marks where t-ring was attached to adapter and a few nicks on edge (visible in photo) which don't affect function at all. $23.00 gets this delivered to you via USPS priority mail.