This is an adapter for converting X-mount lenses to Pentax K-mount. I am selling it because I accidentally purchased it. It is new and unused. It's cheaper than buying it new. How about it for your old lenses? Please refrain from purchasing if you are overly concerned about minor details. There are no smokers or pets in the household. Please refrain from negotiating prices without prior communication. There are no smokers or pets in the household. Please refrain from purchasing if you are overly concerned about minor details.