Store › Standard-Mouth Hydro Flask to 28mm Adapter Image 1 of 2 Image 2 of 2 Standard-Mouth Hydro Flask to 28mm Adapter $7.00 This 3D-printed adapter will allow you to fit the standard tube and 28mm adapter to the Standard-Mouth Hydro Flask Bottle! Quantity: Add To Cart Added! This 3D-printed adapter will allow you to fit the standard tube and 28mm adapter to the Standard-Mouth Hydro Flask Bottle! Reviews Reviewer Name Review Date Star Rating Description Posted on Etsy Product Show More