Its takes far too many of these "small" expensive bottles to do the job.  I've purchased 3 bottles of this brand and previously 4 bottles of the TRG brand to dye so dark brown ankle length boots black and this stuff just soaks right in & the color is still not as black as I would like them to be.  I think I'm going to have to purchase some black fabric spray paint dye to finally get the results I want.