Tried many depth gauge collars etc. They gave up on a previous project and decided to try these. YES, they are relatively expensive, but they WORK and are easy to use. I'm so tired of many other brands of deep sockets and/or sinkers that you have to fiddle with them and they're "improvised" at best. This seems to work very well, depth and sink depth are easy to adjust. Save a few bucks to get one or two of these; and save yourself a lot of frustration from using deep collars. Only given 4 stars for durability and longevity as they haven't been around for a very long time. I've seen some reports of a small problem or two in this department, but so far I don't see any reason why they should have any problems. Say very well done.