... torque and low power loss, connect many pump heads in series or install multichannel pump head for satisfying the different ... 31 Note: N represents the channel number. The YZ series of pump head have 1, 2, 3, 4 ... channels to choose. The DG series of multichannel pump head can choose 1,2,4,6 ... ,8,12 channels. In the DG series types, the numerical value in the bracket represent roller number.For ...