Looking for a new tds meter.

Ok so I am generally scrolling the net looking at new TDS meters.

First i come across is on eBay £5.99 with postage;

http://www.ebay.co.uk/itm/Digital-TDS3-TEMP-PPM-TDS-Meter-Tester-Filter-Pen-Stick-Water-Quality-Purity-UK-/271277774723?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item3f296a5783

Then I come across the same one on the cleaning warehouse website £18.60 with postage;

http://www.thecleaningwarehouse.co.uk/tds-hand-held-meter-938-p.asp

They look the same item to me but a big difference in price ??

Anyone recommend any others?

Daqua do pretty much the same one again with a massive price difference..

http://www.ebay.co.uk/itm/EC-3-Handheld-Conductivity-Tester-EC-Meter-/321246571335?pt=UK_Baby_Baby_Feeding_Bottle_Warmers_Coolers_LE&hash=item4acbc9ab47