I am selling a POC Ventral Spin bike helmet, size large, for head sizes 56 - 61cm in circumference. It's been used exactly once. My brother bought it, realized it was too small, and gave it to me. I used it on one ride before realizing it was also a little tight on me with my winter skull cap underneath. All of that is to say, it's basically new. These things retail for well over $100, so this is a great deal.
Here's a review of the helmet with more specs: https://www.cyclingweekly.com/reviews/helmets/poc-ventral-spin-helmet