Honmofun PH 4.01 PH 6.86 PH Buffer Solution Buffer PH Buffers Easy PH Powder PH Buffer Powder PH Meter Buffering Solutions PH Buffer Calibration Solution PH Meter Calibration Solution USAGE  Make pH buffer powders quickly and precisely without measuring powder. Ideal for testing PH balance of drinking water, pool, aquarium, RO system, Spa and hydroponics etc. Has a longer shelf life than liquid solution (1 year versus 3 years) FEATURES  Designed for portability; Super convenient and accurate; Accuracy: 0.01PH at 25 Degrees Celsius ( 77 Degrees Fahrenheit ). Individual sized packets can be tucked in drawer, bag or suitcase for travel. SAFETY  Meets US FDA and European LFGB Safety Standards. BPA free and free from any other harmful and toxic chemicals. DELIVERY  Ship within 19 hours through Post. Post Office said you'll receive it in 9-20 workdays. Produced by professional factory Honmofun. Shipped by Honmofun Directly. FULL REFUND  Full refund guaranteed. If dissatisfied, please contact us.