These 4 mm Stainless Steel Air Taps are extremely useful if you are intending to run an air-line ring the full length of your system where Air is required in the actual biological filtration systems.
Each 4 mm Stainless Steel Air Taps has its own 4 mm threaded end which can be screwed quite easily into PVC pipework etc. after pre-drilling which allows you to build your own tailor made distribution to supply air.
