Bacteriostatic water is sterile, non-pyrogenic water with 0.9% benzyl alcohol added as a preservative. The benzyl alcohol inhibits bacterial growth, which is what lets a vial be drawn from more than once over a limited period rather than discarded after a single use — the property that separates it from plain sterile water. In research settings it is the standard diluent for reconstituting freeze-dried peptides: the powder in every other vial in this range is dissolved in it before use, and it is the one item here that is not a compound in its own right. Supplied as a 10ml vial; store at 2–8°C in line with the rest of the range.