I was just thinking, that makes me wonder what "black handles" were made from. My first thought was synthetic, but looking at the other materials I'm more likely to guess horn. If it was horn, that would drive the price up a bit.
Whichever material it was, I'm a bit surprised that "the other" is not offered as an option. If synthetics weren't offered, it suggests to me that these were probably some high end razors.
We also know that Mappin & Webb made the "Shilling razor," and they are, at least today, pretty expensive/classy razors, so that too makes me wonder what sort of razors are being referred to in this document.