Here is a link for Hanna Instruments who sell the TDS that we have been talking about: http://hannainst.com/products/promo/usa/usaprmo.htm TDS1 is on special sale for $14.90 USD. I have found Hanna products to be excellent and their service is superior in many ways. Regards Al Baldwin --------------- See http://www.aka.org/AKA/subkillietalk.html to unsubscribe