Rated 4 out of 5 by Funambulatory Great value, functionally complete, but left me feeling disconnected.
These are cheap enough and well made enough, and do exactly as they say they do: an extra layer to go under another pair of gloves to keep the nip off your digits a touch.
They don't fare well near freezing with summer gloves on over them, especially if there's any water in the air, and if you ride fast, but that's probably to be expected. The extra layer is useful in the rain, though.
They're thin enough to fit well under other gloves, and putting either layer on and removal is hassle-free, although they've stretched my Thors ever so slightly, which are now a bit baggy without the liners on underneath (and they were the best fitting gloves I've ever had... oh well).
That ease of pulling on and off the outer-gloves is due to a very slick fabric, which I found causes a bit of float between the two "layers" when riding. That gives a disconnected / squishy feeling at the bars, which does knock my confidence slightly. It's OK for "just riding", but not if you need precise control and / or a bit of force through the bars.
I did not try them on their own on the bike, but I don't think the grippy transfers on the palm and finger tips would last long - leaving only that slick fabric to cling on with! They're not very warm that way, either, obviously, but they feel nice, almost velvety!
16 January 2014