HM Digital's pH buffer solution comes in powder form, so it's lightweight, takes up very little space, is inexpensive and has an indefinite shelf life.
Total volume: 1.2 liters. Each powder packet makes 100 ml of solution (when mixed with distilled or deionized water)
Contents: 3 packets of 4.0 pH, 6 packets of 7.0 pH, 3 packets of 10.01 pH
Extra: Includes one empty 100 ml bottle
Accuracy: +/- 0.02 pH at 25 degrees Celsius
Preparation directions included with the pack