IMO the best lockable system. Used one season and had to quit due to sea sickness and choosing not to continue. Tried a few other methods but whis was by far the most simple and secure.
Amazon sells for $198. Save $100 and buy mine.
Here is a link to my CL ad to see a photo of everything, including two sets of keys.
https://sandiego.craigslist.org/nsd/...625807800.html