I haven’t used a ‘rock stop’ in years. I use a strap with a ring to go around the chair leg and a metal square to put your pin in. Someone in the cello section had one of these and it was so cute, I bought 2 for myself. The first time I used it, it started slipping on the floor in the middle of Brahms Symphony #4. Not good. The floor was not excessively dirty and it was brand new. Disappointed. My stand partner said, ‘spit on it!’ Gross. noticed last week that hers was slipping, too. I guess it...