Need to instantaneously switch from standard E to Drop D and back? The EVH D-Tuna is designed for just that. Simply remove the string locking screw on the saddle put the D-Tuna in its place. The D-Tuna system includes an allen wrench, spring, two spring lock screws, and the unit itself. Finished in gold, it will not only be a stylish addition to your guitar, but a clean and tasteful one as well. With the EVH D-Tuna, drop tuning has never been easier.Features:-1 EVH D-Tuna Unit-2 String lock screws-1 Spring-1 Fine tuning Allen wrench