6-In-Line Ratio Lefty Electric Locking Machine Heads (PRL-8721-L, PRL-8731-L, Select Finish and Button Style)
6-In-Line Ratio Lefty Electric Locking Machine Heads (PRL-8721-L, PRL-8731-L, Select Finish and Button Style)
PRL-8721-LG0
702725245468
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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-8721 and PRL-8731 are left-handed sets of Locking RATIO® Calibrated Machine Heads for electric guitars that use 6-in-line tuners.
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 of six: 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 compatibility 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 50 patents and trademarks around the world.
- JLjason l.Verified BuyerReviewing6-In-Line Ratio Electric Locking Machine Heads Staggered Posts (PRL-9721, 9731, Select Finish and Button Style)I recommend this productRated 5 out of 5 stars4 days agoratio tuners
this is a game changer..best tuners I've used
Graph Tech Guitar Labs Ltd.2 days agoThanks Jason, what guitar did you put them on? Dave D
- MRMatt R.Verified BuyerReviewing3+3 Ratio Electric Locking Machine Heads (PRL-8311, 8322, 8331, 8341, 8351)I recommend this productRated 5 out of 5 stars1 week agoGreat solution for my new PRS SE NF3
I purchased a PRS SE NF3 a couple weeks ago. It is a great guitar, but wanted a locking tuner upgrade. I was originally nervous about the price combined with the "universal fit" thing. I took a chance and ordered these and they have been awesome. The universal plates fit great, although I did have to put in the plates for 3 and 4 together as they are butted up to one another. I was able to use the same screws, but new ones were also provided. I am attaching a photo.
Regarding the "Ratio" feature, it is a game changer. I never expected it to feel different, more accurate, from other tuning heads. But these being geared to each string's thickness/tension is really effective.
If you're on the fence, I hope this helps. This is a unique product with features I would love to see become more standard from premium guitar companies. I am not considering upgrading my Telecaster to Ratio tuners.
Graph Tech Guitar Labs Ltd.2 days agoThanks for the great review Matt. Some models by ESP (Bass), Schecter, Maton, Martin, and the Godin Connaisseur Acoustics are coming with RATIO... it's great to see. (and play!
- MTMark T.Verified BuyerReviewing4+2 Ratio Electric Locking Machine Heads Mini Contemporary Button (PRL-8421, Select Finish)I recommend this productRated 5 out of 5 stars1 week agoWorth the $$$
I’m glad I threw frugality to the wind and bought these tuners. They really are a worthwhile upgrade. EBMM guitars are very stable tuning wise, but the Ratio heads make getting there so much easier!
Graph Tech Guitar Labs Ltd.2 days agoWell said Mark! Dave D
- ADAnthony D.Verified BuyerReviewing6-In-Line Ratio Electric Locking Machine Heads (PRL-8721, 8731, Select Finish and Button Style)I recommend this productRated 5 out of 5 stars1 week agoGreat addition
This was an easy swap to upgrade to locking tuners. Excellent quality and tuning stability seems rock solid so far.
Graph Tech Guitar Labs Ltd.2 days agoThanks Anthony! What guitar did you put them on?
- SRScott R.Verified BuyerReviewing3+3 Ratio Electric Locking Machine Heads (PRL-8311, 8322, 8331, 8341, 8351)I recommend this productRated 5 out of 5 stars2 weeks agoIdeal LTD/ESP solution.
These Ratio tuners are the absolute best drop-in solution for LTD/ESP tuning issues. Simple and quick to install, without the adaptive templates, and the tuning results are exceptional. I use a strobe bench tuner, and these machine heads yielded the most accurate results that I've ever seen. Highly recommended.
Installed on an LTD EC-1000 Deluxe, as shown in photo.
Graph Tech Guitar Labs Ltd.2 days agoThanks Scott, and thanks for the photo! Play On! Dave D