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4 String 4-In-Line Bass Ratio Open Back Classic Clover Leaf Button (PRB-4401)

4 String 4-In-Line Bass Ratio Open Back Classic Clover Leaf Button (PRB-4401)



Regular price $195.44 USD
Regular price Sale price $195.44 USD
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RATIO® patented gear technology
RATIO® - Calibrated Machine Heads incorporate different string gauges into the tuning equation.

From Low E to G - 48:1, 36:1, 25:1, and 23:1.

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. 


Bass Ratio animation

The PRB-4401 is a right-handed set of RATIO® Calibrated Machine Heads for BASS that use a 4-in-line configuration.


In order to achieve higher gear ratios, Ratio are the world's first machine heads using a double envelope gear design with a hardened steel gear. Amazingly smooth and super strong.


Headstock Configuration 4-in-line  Ratio Tuned Machine Heads: The New Standard In Tuning Technology


Gear ratio: unique for each string position - one turn-one tone
Peg holes diameter required: 0.720" (18mm)
String post diameter: 0.547" (13.9mm)
String post length to string hole: 0.807” (20.5mm)
Weight per single machine head: 3.5oz (99.3g)
Weight per set of four: 14oz (397g)
String diameter up to 130 gauge
Includes 4 machine heads, mounting screws and bushings

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Rated 5.0 out of 5 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
  • RL
    Raymond L Lawrence J.
    Verified Buyer
    I recommend this product
    Rated 5 out of 5 stars
    1 week ago
    The best tuners money can buy.

    Ratio tuners. It the only tuners you need to know. Period. I love these

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