"The combs work fast with a 12A 5kg combi hammer and last quite well working on both lime and cement mortars. It is just the right thickness for teasing off lime-mortared courses of bricks, because lime is trowelled so much thinner than cement. Very few bricks broke and the combs are quite handy for excavating the frogs, once you get the hang of it.
When the chisel gets hot, which is after about 10 minutes of constant use, the comb tends to become loose and will fall out, if you are not careful. I had to keep a bucket of cold water up on the roof with me, to cool it quickly down."