What does a 2X after the PANTONE color, i.e., PANTONE 185 C 2X, mean, and are these colors still available?
2X = double impression, usually referred to as a 'dry trap', where a color is printed, dried back, and then overprinted a second time to produce a more intense color.
2X colors were deleted from the PANTONE MATCHING SYSTEM products back in 2000. The reason for this is because they were rarely used, and caused unnecessary confusion when they were specified.
While it is still technically possible to print double-impression colors, Pantone does not currently provide examples, and thus any existing guides or books would no longer be considered color-accurate.