OUR LUTHIER TOOLS ARE 100% ORIGINAL. For any questions or information, please feel free to contact. 

Understring Crowning File


Understring Crowning File is a proper fret crowning file designed to work underneath the string without altering the playing condition of the instrument. It comes with V-shape or the old style concave file. It is ready and it will be in stock soon!




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Price list

REMINDER: to buy our tools please make sure to visit the How to buy page first. Thank you 

-Prices are in USD

-Shipping price is typical for 1 tool and 1 Kit

-RED is out of stock

-RR Kit is accessory (sold only with a leveling tool)

-Final shipping price may vary depending on volume, weight and final destination of the order

R.M.KATANA for guitar $225 +Shipping  $40
R.M.KATANA for bass $255 +Shipping  $50
R.M.nanoKATANA *uke $165 +Shipping  $36
R.M.BUZZ-Killer spot lev.  $80 +Shipping  $25
R.M.LITE for guitar  $40 +Shipping  $35
R.M.LITE for bass  $55 +Shipping  $38
RR Kit (reload/refinishing)  $38 Accessory  
LittleBone #400 grit  $25 +Shipping  $18
LittleBone #150 grit  $20 +Shipping  $18

LittleBone DoubleAngle #400 grit

 $28 +Shipping  $18
LittleBone DoubleAngle #150 grit  $28 +Shipping  $18

LittleBone DoubleGrit


 $28 +Shipping  $18
LittleBone ice #320 grit  $28 +Shipping  $18
LittleBone ice #150 grit  $28 +Shipping  $18
LittleBone ice Special  $35 +Shipping  $18
Digital Action Gauge  $34 +Shipping  $18
FRET RAIL mini  $18 +Shipping  $18
Feather File for nut   $20 +Shipping  $18


About Rectify Master

RECTIFY Master is a brand specializing in Fretboard Optimization. It focuses on research and development of quality set-up systems for a more fluid playing, with over 30 years experience.




TOKYO, Japan

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