Simon G.wrote a review of Gore Wear C3 Gore Windstopper Toe Cover on May 9, 2019
Familiarity: I've put it through the wringer
For such a thin material, it's surprising how well they work. There's really no insulation value, but in blocking the wind they really do go some distance to keeping your toes warm on cool days. For well-ventilated shoes, consider taping over air vents in the soles to really help them work.
That said, I've worn these out after a couple of seasons. The underside isn't reinforced at all, and clipping in causes enough wear that holes have formed. I'd consider the Castelli Toe Thingies, which are both reinforced and much warmer.