One of my sons played an old acoustic guitar at different scout events, but he was always unsatisfied because of the missing possibility of applying a guitar strap. We had enough straps at home, but this old guitar was without any strap button. So I bought the Harley Benton Strap Knob Set for this purpose. It consists of 2 buttons and 2 screws from metal chrome plated and 2 washers from leatherette(?). The mounting is easy, but in such situations you have to prepare it accurate and centre punch and pre-drill the position of the screw hole. So you can avoid small damages, like scrapers on the surface of the guitar. Please don't forget the washers (leather side to button!) and don't overtighten the screws! The plastic packing is clever, because you can open and close it by hand. You don't need any tools like a knife or scissors etc. Bravo Thomann, we can use the packing for a long time and don't have to throw it away! The set has a really good quality, a great price and value and my son is very happy.