Ever wonder why Rogers called their wrap onyx and Slingerland called theirs agate? This from Wikipedia:

"Onyx is a banded variety of the oxide mineral chalcedony. Agate and onyx are both varieties of layered chalcedony that differ only in the form of the bands: agate has curved bands and onyx has parallel bands. The colors of its bands range from white to almost every color (save some shades, such as purple or blue). Commonly, specimens of onyx contain bands of black and/or white."

It has seemed that the Slingerland version is a bit more rounded than the Rogers version, which tends to be more parallel. The new wrap from Precision also seems to be different from Jammin Sam, the latter being more rounded like that used by Slingerland.