Ratio by Graph Tech (12:1 to 39:1) Electric Locking 4x2
Ratio by Graph Tech (12:1 to 39:1) Electric Locking 4x2
PRL-8421-C0
702725245376
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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, 35:1, 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.
The PRL-8421 is a right-handed set of Locking RATIO® Calibrated Machine Heads for a Music Man, or other 4 x 2 style headstock.
It has a mini contemporary button.
It has a two-pin casing that can be used as is, or with our Patented InvisoMatch Mounting Plates [opens in new tab].
4 different sets of InvisoMatch mounting plates in brushed aluminum are included to make installation on most guitars fast and accurate by using your existing screw mounting holes.
Gear ratio: unique for each string position - one turn-one tone
Peg holes diameter required: 13/32" (10mm)
String post diameter: 0.236" (6mm)
String post length to string hole: 0.910” (23mm)
Weight per single machine head: 0.083lbs (38g)
Weight per set: 0.496lbs (225g)
String diameter up to 72 gauge
Includes 6 machine heads, mounting screws and bushings
Includes complimentary 4 sets of aluminum mounting plates
Invisomatch Adapter Plates
InvisoMatch® Adapter Plates offer the easiest solution for installing RATIO® Tuned Machine Heads on your guitar
Simply select the installation plate design that matches the screw/pin hole location of your factory installed machine heads. You’ll be up and running within minutes, perfectly installed and aligned. Stay classy you axe master.
For stunning accuracy and response... upgrade to RATIO® Machine Heads with it's patented Multi-Geared Tuning Technology. The new standard in tuning.
No drilling, perfect alignment, fast installation!
The alignment of the machine heads is perfect, no holes to drill or fill, ideal for vintage instruments. Premium finishes are available for order, including chrome, nickel, black, and gold. Additionally, each set of RATIO® Tuners comes with four complimentary brushed aluminum InvisoMatch® Adapter Plates.*
*Each set of Graph Tech RATIO® Machine Heads includes four sets of brushed aluminum InvisoMatch® Adapter Plates. These plates are not included with bass or open back tuners. For a customized appearance, are available in finishes such as chrome, black, nickel, and gold.
Find your InvisoMatch® Adapter Plates fit (download the guide!)
Please note that our InvisoMatch® Adapter Plates list is regularly updated. Before placing your order, ensure the selected plate matches your guitar's specific model and variation.
* Some guitars may have different configurations, so double-checking is essential.
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Graph Tech has created some of the world's most recognized products and brands in the music industry
The list of industry firsts include the world's first self-lubricating nut in 1983, String Saver Saddles the first saddle to drastically reduce string breakage, TUSQ man-made ivory, and Ratio machine heads.
Graph Tech has over 65+ patents and trademarks around the world.
- KKristopherReviewingRatio by Graph Tech (12:1 to 48:1) Electric Locking 4x3I recommend this productRated 5 out of 5 stars3 days ago5 Stars
Best tuners
- CTColin T.Verified BuyerReviewingRatio by Graph Tech (12:1 to 48:1) Electric Locking 7 in-LineI recommend this productRated 5 out of 5 stars1 week agoRatio locking tuners
Fantastic quality tuners. Excellent service. Recommended.
- SWSteven W.Verified BuyerReviewingRatio by Graph Tech (12:1 to 39:1) Lefty Electric Locking 6 in-LineI recommend this productRated 5 out of 5 stars1 week agoLove these things. On all my guitars
My only request would be to be able to buy them without the mounting hardware, I have a mountain of unused mounting hardware that I never use.
- DPDale P.Verified BuyerReviewingRatio by Graph Tech (6:1) Ukulele Tuner Regular Button (4 pc set) Black #PRU-4004-BKI recommend this productRated 5 out of 5 stars2 weeks agoGreat tuners!
Ordered these directly from Graphtech Canada and they arrived really quickly in UK. Quality is excellent, they don't look as great as they really are. Functionally the best ukulele tuners I've used.
- CKChristopher K.Verified BuyerReviewingRatio by Graph Tech (12:1 to 39:1) Electric 3x3 WaffleI recommend this productRated 5 out of 5 stars2 weeks agoThese tuner are perfect in everyway
I put these tuners on all my guitars that originally had Kluson deluxe style tuners. Make sure to purchase the seperate bigger size bushings if you are putting them on modern Gibson USA guitars. Finally a split tuner post got 3x3 guitars. The ratios gearing makes perfect sence once you get used to it. I would never go back. I used to use Sperzals in everything, but am starting to have a hard time getting them anymore, but I am super glad these are available vecause I like them better.