This product came with very simple instructions, taking off old strap buttons and replacing with Warwick Straplock buttons using the screws provided, then placing the lock onto the strap and tightening it with a wrench/spanner of the correct size. These straplocks are very sturdy and very easy to fit, I have fitted them on three different instruments (in black and chrome) and I did not have to drill any holes, the whole installation can be completed with a crosshead screwdriver and a spanner and provides a very reliable system, I could not find any faults with these straplocks and the release buttons are easier to use than those on other brands. As usual with Warwick these are of high quality and work extremely well!