A left timing ring arm (110 BCD, 5 bolt with 'hidden' bolt) which could be used for front or rear. This crank is only compatible with a tandem (or a non-standard left-hand drive system). Square taper interface. 175mm in length. Bolts, ring, and accessories not included. Right arm is also not included, only the left/timing arm. Please see photos and condition description. (This may require you to expand "About This Item" on mobile.) This is being sold by Bike Farm, a 501(c)3 all-volunteer co-op dedicated to every aspect of bicycle education, from safe commuting to repair. Our mission is to provide a space where people can learn about the bicycle and build community around promoting sustainable transportation. We strive to demystify the bicycle in order to impact our community in a healthy and positive way. Items generally go out next day, Monday through Thursday. Ships via USPS Ground Advantage or Priority Mail.