Graph Tech - Ratio tuned machine heads for electric guitar. 

One turn equals one tone on every string. 

Vintage, waffle-back design. 

Open back with hardened steel gears. 12:1 - 39:1 gear ratios. 

Round, vintage style buttons.

Singles.

6-in-line.

Nickel.

Note: Vintage specification (for 11/32"peghead holes) not a direct replacement for a modern machine head.