Essentials EC Tester
Professional waterproof and with replacement probes.
ESSENTIALS pH Pro & EC Pro meters are professional quality, reliable and available with replacement probes. They have a large screen to view results and are very easy to use. They have screw calibration and come with a built in small screw driver.
The meters have a lifespan of about 1 to 3 years depending on rate of sampling. (Units are good for 365 accurate tests.)