What Electro-Harmonix say:
The Steel Leather is the first dedicated expander designed for bass guitar. It lets you cut through any live performance with presentation definition. An expander is the reverse of a compressor, and the enhanced attack will ensure that your bass does not get lost in performance.
Quick Specs
True bypass
Tough and compact die-cast chassis
9-volt battery included
Optional 96DC-200BI power supply available
Dimensions in inches: 2.75 (w) x 4.5 (l) x 2.1 (h)
Dimensions in mm: 70 (w) x 115 (l) x 54 (h)