A tunable optical filter apparatus and method are disclosed. A support includes a plurality of spacers disposed between the applicators. The first voltage level shifter may be selectively coupled between the source and the gate during the ON phase, and the second voltage level shifter may be selectively coupled between the gate and the source during the OFF phase. The linear piston adjustment can also have a worm gear drive mechanism for controlling linear piston movement. The wireless transmitter is provided in the shoe and electrically connected to the power supply for wireless communication of data with a remote device.