HI70024P is a premium quality 35.00 ppt salinity calibration solution that is NIST traceable and contained in portable single-use sachets. Each sachet has the lot number and expiration date stamped on it and is made of light block foil ensuring freshness each time one is opened. Hanna's line of calibration solutions have been specially formulated to have an expiration of 5 years from the date of manufacture for an unopened sachet. The HI70024P is for 25 sachets containing 20 mL of solution.