Nalgene 3645 Self-Zeroing Buret Kit makes any plastic or glass 25- or 50-mL buret self-zeroing, economically and easily. Saves you money over costly glass self-zeroing burets. No more funneling; hazardous, wasteful spills are eliminated. Can be used with almost all aqueous titrants. Set adjustable fill-tube to zero mark on buret. Squeeze bottle to fill buret* just above zero mark. Release and excess liquid returns to bottle and titrant falls to the zero mark. To switch to a different size buret, simply reverse the adapter.