C+Bio Fizz Effervescent by Designs for Health，144G (5 OZ).

What the brand says

This delicious, effervescent, orange-flavored powder easily provides therapeutic dosing of vitamin C and bioflavonoids. Potassium bicarbonate is included in this formula as a buffering agent and to give it "fizz." Also included are quercetin, hesperidin and rutin, which are all natural bioflavonoids found in citrus fruits. The potassium bicarbonate was added to this formula as a buffering agent. Quercetin is also found in red wine and tea.