The ESP Flicker II bridge/tremolo is a tremolo from the mid 80's made by ESP. It wasn't used very often but has a unique design. It consists of a pivot bar which can be placed in the normal position of the six screws where you normally install a standard tremolo in. The pivotbar only needs (the middle) four screwholes. The other part of the tremolo has two knife edges that hinges against the pivot bar. There is also the ESP Flicker I and ESP Flicker III tremolo. They had a similar concept but made use of a a rotating hinge.