Fender Strap Blocks 4-Pack, Black (2) and Red (2)

The most reliable and hassle-free instrument strap lock system ever devised. No need to remove or replace existing strap buttons on your guitar; just slip easily installed Strap Blocks over the existing strap buttons and that's it - you're ready to go, with your strap locked securely in place.
Strap Blocks work with most OEM strap buttons, and are available in convenient four-packs.