FU-Tone, originally known as Floyd Upgrades (FloydUpgrades.com), is a guitar hardware company founded by Adam Reiver and based in Washington Crossing, Pennsylvania. The company grew out of Reiver's work on the EVH D-Tuna drop-D tuning device for locking tremolos, eventually expanding into a full line of high-performance guitar upgrade parts. FU-Tone is best known for its Big Block sustain blocks — available in brass, titanium, and copper — designed to replace the stock zinc blocks in Floyd Rose and other locking tremolo systems to improve sustain, clarity, and note separation.

Beyond tremolo blocks, FU-Tone manufactures titanium saddle inserts, noiseless polymer-coated springs, tremolo stabilizers, tremolo arms, and the Pickup Mounting System (PMS). The company also produces its own line of electric guitars — FU-Tone Pro guitars — that come factory-equipped with the brand's full suite of hardware upgrades and proprietary pickups. Their product range covers upgrades for Floyd Rose, Gotoh, Ibanez, PRS, Jackson, Peavey, Strat, and 7-string tremolo systems, as well as parts for hardtail guitars like Les Pauls and Telecasters.

FU-Tone's Big Block has been adopted by a number of prominent guitarists, including Slash, Warren DeMartini, Nuno Bettencourt, Eddie Van Halen, Steve Vai, Joe Satriani, Neal Schon, Kirk Hammett, Phil Collen, and Pete Thorn.

FU Tone has 2 products cataloged on Equipboard, including Miscellaneous Guitar Parts and Guitar Bridges and Tailpieces. Their gear is featured by 2 artists, with the strongest followings in Rock. Notable users include Doyle Wolfgang von Frankenstein and Joss Allen.