The CML unit is 11 pin DPDT while the Macromatic COKP is SPDT 8 pin–the socket must be changed and some rewiring done; the CML unit has a drop-out voltage setting fixed at 95% of the pick-up setting while the Macromatic COKP has adjustable drop-out setting of 50-95% of the pick-up setting; the CML unit has a reset button to de-energize the relay when pushed while the Macromatic COKP does not