I sent in my BM Park Avenue pre-production 450 to have the chain/hook setup replaced. It was removed by the previous owner that I got it from in a trade. Not only did the Benchmade folks replace the chain/hook they also sharpened the blade and lubed the action for me. Now it opens like it had a spring in it. The only cost was $5.00 for shipping and handling. Way to go BM!