Floyd Rose continues its legacy of innovation with the brand new surface-mounting FRX Tremolo System for Les Paul, SG, and Flying V-style guitars. The FRX is a direct swap for the Tune-O-Matic and stopbar type bridge system, using the existing mounting stud holes and requiring no routing whatsoever. The locking nut mounts behind your guitar's existing nut, in place of the truss rod cover. The FRX locking nut has mounting holes on the left and right; only two wood screws have to be installed to mount the nut. *NOTE: On some Les Pauls, particularly LP Customs, the neck angle is not sufficient to allow the FRX to work without slight modification to the body. The receiving portion of the spring tension transfer rod on the base plate extends slightly below the bridge and may rest on the body unless a tiny channel is routed. This tremolo system is not compatible with the Tony Iommi Signature SG.