Solid steel, chrome plated Trimax Puck style lock.  6 pin re-keyable cylinder.  Slightly thicker than the MasterLock brand.  This is probably the best lock for the money in the “better” category. These locks ship free with the purchase of a Ft. Knox Locks coupler lock. If selection of “Purchased with a Ft. Knox Lock” is made and a coupler lock is not included in the order a separate invoice via Stripe will be sent to customers email.  Call us (855-369-6723) if you have ordering questions regarding shipping or quantities of keyed alike locks.