A complete nozzle is $ 11.95, TEE 6mm is $2.11 and the reducer 6/4 is
$ 1.20 Makes a total of $ 15.26. There is an alternative. The 10 nozzles works also on a 4 mm pressure hose, only the performance is a little less. That means there is less water out of the nozzles, but the spray patern is still good. You spare than the reducers and the TEE 4mm is cheaper. If this is a solution i will check the performance with 10 nozzles on one pump with 4 mm hose for you.