Hello, up for sale is a NOS / New Rans Recumbent Adjustable Seat Strut. For single strut Rans recumbent seats like on the Trek R200 recumbent bikes (made by Rans). Distance between eye centers on each end adjusts from 28-41cm and secures with a quick release. Longest measurement (41cm) was taken with the strut safely 1 1/2" in the sleeve. The wide frame mount end is 45mm wide with a 5mm hole. The thicker small machined end is 20mm wide with a 6mm hole. Hard to find these struts, as Rans is now out of business. Great for recumbent bike frame builders. Left-over stock from Terry Osell, a legend in custom recumbent bike fabrication. Buyer to pay $8.80 USPS Priority Mail shipping with tracking. Thanks for looking.