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3+3 Ratio Acoustic Open Back Tuners (PRN-3411, Select Finish)

3+3 Ratio Acoustic Open Back Tuners (PRN-3411, Select Finish)



Regular price $178.19 USD
Regular price Sale price $178.19 USD
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Select Finish
Select Button Style

RATIO® patented gear technology
RATIO® - Calibrated Machine Heads incorporate different string gauges into the tuning equation.

From Low E to High E 39:1, 24:1, 20:1, 14:1, 20:1, 12:1.

We balanced the gear ratios to each string simplifying the tuning process.

With RATIO®, a half turn is a semi-tone!

Every string reacts the same to any tuning adjustment. Predictable, precise tuning, on every string.

RATIO Machine Heads explanation video


The PRN-3411 is a right-handed set of open back RATIO® Calibrated Machine Heads for acoustic guitars that use 3+3 side tuners.

It has an intricate skeletonized button and finish selection.


3+3 tuners setRatio Tuned Machine Heads: The New Standard In Tuning Technology


Gear ratio: unique for each string position - one turn-one tone
Peg holes diameter required: 0.346" (8.8mm)
String post diameter: 0.236" (6mm)
String post length to string hole: 0.827” (21mm)
Weight per single machine head: 0.056lbs (25.5g)
Weight per set of six: 0.338lbs (153g)
String diameter up to 72 gauge
Includes 6 machine heads, mounting screws and bushings


Rated 5.0 stars
Based on 1 review
Total 5 star reviews: 1 Total 4 star reviews: 0 Total 3 star reviews: 0 Total 2 star reviews: 0 Total 1 star reviews: 0
100%would recommend this product
1 review
  • RS
    Robert S.
    Verified Buyer
    I recommend this product
    Rated 5 stars
    3 months ago
    New Martin SC-13E

    I loved that Martin put these tuners on there new SC-13E and thought it would be advantageous for me to do the same with the older model. They where very easy to install and they sure make a big difference when tuning. A great product.

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