Hi chris, The dos injector has a rotating head which enables you to decide the % you wish to have the dilution level at... I have never come across such a device myself. I saw it being used in a large green house. the mechanics seemed quite simple, one end you plug your hose pipe, it then draws up the hypo through a suction pipe and comes out the other end diluted.. though the exit flow rate is all dependant on your water feed.
