Check the listing for details. v2 Rotor Master 540 brushless Motor Tuning Tool Donathen RC DRC. Condition: New. Listed at 139.99 USD. This is a device to measure the strength of your 540 rotors. New v2 design! These are made to order and will ship within 5 business days of purchasing. Please contact us prior to purchasing, so that we may know your color preference. Features & Specifications: Power range 7-12v (2s or 3s battery, or power supply)Measures 3 area of your rotor strength (left, right and middle)Measures current and max value of rotor in 3 areasReverse Polarity ProtectionOptimized calibration, for more accurate readingsInstant data reset buttonRevised rotor cradle for more consistent rotor readingsMeasures up to 4000 GaussLCD ScreenHandcrafted in the USA!Comes with protective EVA zipper CaseTested from the manufacturer, for calibration and working condition FREE Case colors: Black, Orange, Blue, Jade White, Matte Ivory, Green, Bambu Green, Matte Lilac, Purple, Matte Charcoal, Matte Red, Yellow. The following are available at $5 extra per item: Iron Gray, Cobalt Blue, Blue Silk, White Marble, Red Granite PCB Colors: Black and white Check out their video title="YouTube video player" src="https://www.youtube.com/embed/0xb_N9yZejc?si=MRtArjJbwLcWhsPP" width="560" height="315" frameborder="0" allowfullscreen="allowfullscreen"> Plese note that all items purchased from me will have complimentary insurance on the item for the value purchased. Additionally if the purchased item is used, changed condition, has been altered, quantity sold has been altered, or any other variation from the listing full returns are not available, partial refunds are subject to what has changed.