BBE OptiComp Optical Compressor Guitar and Bass Pedal Studio-Grade optical compression with Output and Threshhold controls. 1MEG Ohms input impedance for proper pickup loading and 1K Ohms output impedance when engaged. 1 per cent metal-film resistors for consistency, High-voltage poly caps for better tone and Military-spec circuit board for reliability. Blue status LED for high visibility and low power consumption and Easy access battery compartment. True hardwire bypass.