HANNA HI 7007L BUFFER SOLUTION PH 7.01 500 MLHI7007L is a premium quality pH 7. 01 calibration solution designed to deliver precise pH measurements. Each bottle is clearly labeled with the lot number and expiration date for traceability, and comes with an airtight, tamper proof seal to maintain the quality of the solution. Hanna's pH calibration buffers are an ideal choice for ensuring accurate pH readings every time. Key Features: Airtight bottle with a tamper proof seal to ensure solution