From Allparts:
True Lok
True Lok series tuning keys were designed to deliver impeccable tuning stability. With options available for most vintage and modern guitars, every player can upgrade their instrument for Lok-solid performance!
Mid-Size 6-In-Line Locking
Designed for stability, accuracy and rigidity, our True Lok Mid-Sized 6-in-line locking tuning keys feature staggered posts that eliminate the need for a string guide, an 18:1 gear ratio for more accurate tuning, and an easy-to-use lock wheel on the back of the key that offer better tuning stability as well as making string changes quick and easy. Designed to be more compact than full-sized keys for use in smaller 3x3 headstocks, these keys offer a sleek, modern look that would complement any guitar!
Features:
Locking key with lock wheel on back of housing
Orientation: 6-in-line staggered post
Housing Size: Mid-sized
Gear Ratio: 18:1
String Post: Zinc
Worm Gear: Steel
Gear: Brass
Key Housing: High density die-cast zinc
Button Style: Metal square-style
Post Diameter: 6mm (requires 10mm hole for screw-in bushing)
Tension washer added to base of string post prevents "post wiggle" for better sustain and more stable tuning
Nylon washers and steel button shaft ensure smooth feel
Hardware Included: 6 screw-in bushings 6 dress washers 6 screws
