tri meter

is this meter any good?
http://www.ebay.co.uk/itm/EC-CF-pH-oC-TDS-Tri-Meter-Hydroponics-Tester-pen-/300580332179?pt=UK_HomeGarden_Garden_PlantsSeedsBulbs_JN&hash=item45fbfbe293

Ive not used one myself but ive seen other growers say there pretty good, at that price you really cant go wrong mate.