Shimano something (not specified in the bike spec). The cassette was worn and needed replacing at 1446m, but the chain was only 0.38%. I put the chain to one side and fitted a Sram PC-1130 (at the time, it was the only chain I could get that was at least 120 links long). When this one has worn down to 0.4% or so, assuming the new cassette is still OK, I'll refit the old Shimano chain. (And keep the PC-1130 for later).