Hi Karen. I found these glasses to be wider than other Costas I have (Brine, Skimmer), but the temple length is slightly shorter. I have a pretty narrow face, and these glasses are a little wider than I would like, but not too wide. Hope that helps.
I know BC has these listed as M/L, but they're listed on Costa's site as M, so I'll assume they're actually supposed to be size M. Anyways, I have a few other pairs of Costas of varying styles all listed as M/L on Costa's website and they all fit pretty good, despite me having a narrow face. The Caballitos are somehow wider than those styles despite being listed as a smaller size. Seems Costa's sizing pretty much only pertains to temple length and not frame width. Just wanted to make sure people are aware.
Anyways, they still fit pretty well and they're lighter than any of the other styles I have. All around, a solid pair of shades.