S2.5 Allen key
Press down the black buckle and pull the Teflon tube upwards.
Use an S2.5 Allen key to unscrew the fixing screws of the four-input and one-output assembly.
Use an S2.5 Allen key to unscrew the fixing screws of the four-input and one-output assembly.
Insert the four Teflon tubes into the four-in-one-out assembly in sequence, and check whether the four Teflon tubes are inserted in place and are not loose.