The narrow mouth is the original design from Hydro Flask. It It is ideal for keeping your liquids chilled all day. Ice cubes from standard refrigerator ice dispensers fit perfectly through the narrow mouth.
Each Hydro Flask is cast from double wall vacuum insulated food grade 18/8 stainless steel
Vacuum flask will keep contents cold for 24 hours or hot for 12 hours
Vacuum design also prevents scorched hands from hot drinks and condensation from cold drinks
18/8 stainless steel is inherently naturally resistant to odors and bacteria
Ice cubes from standard refrigerator/freezer door ice dispensers fit perfectly through the narrow mouth