Schaller BMFLCH 547 Bass Machine Head BMFL - Open 4 left - Chrome BMFL openWith longer button and bigger base plateRatio 1:20Bore 17,5 mmWeight 103g/itemBMF buttonMounting: 4 screws/counterfortCompared to the BM series, a longer string post and a larger button plus a bigger base plate make it a perfect replacement machine headfor Fender Jazz and Precision basses. Counterfort-mount.