The Counter Top Water Filter/Purifier, is very easy to install and adapts to virtually any tap.  The tap needs to have a thread on it so the diverter valve can be connected to it.  Simply unscrew the aerator off the bottom of the tap and then screw the diverter on to it.  It will go straight on the thread if it is on the outside of the tap.  If the thread is on the inside of the tap, then a 3 way tap adapter will need to be used.  For that, place the 2 rubber washers on the 3 way tap adapter and then screw the adapter up inside the tap.  Once that is done, you can then attach the diverter straight on to it.

Tap adapter instructions download here 

If there is no thread on the tap at all, we, have a couple of options.  The best option is to change the tap completely with either a wall mount one if the tap comes out of the wall, or a hob mount if the tap comes out of the sink.  The taps cost around $20.00 - $30.00 from any reputable store.