Good condition, used Ritchey WCS 1-Bolt Mast Topper / external seatpost for carbon frames. 34.9 mm X 50mm, 25mm offset. Provides about 20 mm of adjustment up and down your integrated seat post / frame, which is plenty if your seat post is cut to the correct height. Please let me know if you have any questions. What do you see in the pictures is what you get. Thanks!