pH 4.01 Buffer Solution for electrode calibration and care. Color-coded for easy identification. REED R1404 Offers The pH 4.01 Buffer Solution is manufactured and ready to use in accordance with and traceable to NIST publication 260-53 (PB 248-127) to ensure quality and accuracy. Label includes a table to display what the pH value should be given the buffer solution temperature. Features 4.01 pH Buffer Solution (25°C) 16.9 fl oz (500ml) bottle with viewing strip and childproof cap Color-coded red for easy identification ±0.020pH accuracy Certificate of Analysis available upon request Included REED R1404 Buffer Solution, 4.01 pH