The model can be used to mix beverages inside a small bottle or can.
If you want to, you can also use the smaller one as a keychain to always have on on hand :)
It should fit every standard sized can and bottles as small as a Coke 0.33l.
Sizes:
Inner diameter (thinnest part): 1cm
Outer diameter (thinnest part): 1.3cm
Small funnel inner diameter: 3.3cm
Big funnel inner diameter: 4.67cm