conjunction with Floyd Rose. Other locking systems Several other "locking" type vibrato systems have been developed, but none of these have gained the popularity that the Floyd Rose or vintage Fender "tremolo" systems have. The most notable of these is the cam-operated Kahler Double-locking tremolo, which is similar in practical use, but not in design, to the Floyd Rose. Another system that emerged in the 1980s was the Steinberger TransTrem system (meaning Transposing Tremolo). Ibanez have their own range of double-locking vibrato systems on their range of guitars. The Edge III tremolo, featured on their low-mid range guitars, is a very similar bridge to a Floyd Rose. It features a pop in/out arm and lower profile tuners. Another system is the Edge Zero, which has what Ibanez calls the Zero Point System. This system lets the guitarist lock the guitar's floating state for tuning purposes. There is also the Edge Pro tremolo with a very low profile. Possibly its most notable feature is that it is designed to take strings without the removal of the ball end (or stringing backwards with the ball ends at the headstock). The Edge Pro also comes in a version called the Double Edge Pro, which has piezoelectric pickups for acoustic sound. In 2007, the Super-Vee company developed a double-locking vibrato system that requires no modifications to the body or neck of the guitar. This system received a patent for its "Blade" technology, which is based on what they call "frictionless action." This action removes the contact pivot point that other vibrato systems rely on, aiming to eliminate wear irregularities that cause tuning instability. Super-Vee also received a patent for their side-locking nut system, which does not require instrument modification. The Steinberger TransTrem, like the Floyd Rose Speedloader, requires special strings that can only be used on the TransTrem unit. However, the TransTrem had the novel design that the bar could be pushed in to "transpose" the tuning of the entire unit to various other keys. The system saw limited use (mainly due to its high price and limited string availability), although Edward Van Halen had continued to experiment with the system. Notable Van Halen songs where the TransTrem can be heard include "Get Up" and "Summer Nights", from the album 5150. Vibrato system additions Various add-on gadgets strive to improve vibrato systems. An issue with nearly all vibrato systems is that bending one string