Not to sure what species would go for them as its not a natural bait for most fish. I supose they could possibly work for Wrasse as they have teeth that could cope with them.
Cheers keith
I think you mean limpets , yes i have tried them several times but never had a bite on them. They are meant to be ok for wrasse and i expect bream would take them . Just not on my hook.
I caught a limpet once ha ha, I was fishing off a pier when my hook got snagged on one of the pier supports, it suddenly came free with a quite large limpet attached minus its shell. I had to ask other fishermen what it was because I was puzzled about what it was.