I have two Orion (Vixen style) 13" long dovetail bars, with cone-error adjustment screws on each end. Both are in excellent condition; I've only mounted rings on them once to try them out. I have since switched to a Losmandy style dovetail and they are no longer needed. http://www.telescope.com/control/product/~category_id=mount_accessories/~pro... These are $16.98 each, plus shipping, new from Orion. I will sell the pair for $25 if you pick them up. No tube rings are included.