MusicNomad's Acousti-Lok is a strap lock adapter that adds the safety and flexibility of using strap locks to your acoustic guitar without permanently modifying it. Designed to be used with Schaller-style strap locks (not included), Acousti-Lok's strong solid brass construction gives you the security you have been looking for. With different Acousti-Lok designs to choose from, make sure you find the one that is compatible with your acoustic guitar output jack. Acousti-Lok was not designed to be used on recessed or flush mount jacks.