Hanna pH 7.0 Calibration Solution 500ml crystal star Protect your valuable crops and 4 L x 9 Protect your valuable crops and plants from abiotic stress with Lost Coast Plant Protector plant wash concentrate Hardwire: Field configurable Air tight bottle with tamper proof sealEnsures quality and freshness of solutionColor coded label for easy pH buffer value identificationEasy to identify different buffer valuesSolution does not contain any dyes that may stain the reference cell of a pH electrode Hanna’s line of calibration buffers have been specially formulated to have an expiration of 5 years from the date of manufacture for an unopened bottle