I've owned a Myerchin B300P for years. Recently I bought a used A377P on an ebay auction. The seller, south Carolina Gov. surplus, sent me a second knife, along with a note that the spike on the A377P was "a bit loose." Seller offered me to keep bothe knives or return both to them for a full refund. The spike was more than a bit loose. It didn't lock at all. I kept them.
I did, however, write myerchin to inquire about the cost of repair on the double lock mechanism-explaining that I had bought the product used on ebay. John Myerchin sent me a note asking that I send the kife to him. Less than a week later, I have a brand new A377P. Myerchin replaced the kife at no cost. Obviously they did not have to do that as I am not the original purchaser. So I highly recommend Myerchin and their lovely rigging knives. And I'm grateful for a very good experience in dealing with the company.