What are the functions of different brush heads of mascara tube?

Comb-shaped brush head, a good helper for dredging eyelashes
If the eyelashes are sparse, the eyelashes tend to stick together when using mascara, and the mascara of the brush head can dredge the eyelashes while applying, eliminating the step of using the eyelash comb.
Double-headed mascara 1 has 2 makeup effects
The large and small double-headed design can treat the upper and lower eyelashes separately. Some brands also design this double-headed design as one with thickening effect and the other with elongated effect. It is convenient for you to have two makeup effects with only one.
Extra-large brush head style, brush out false eyelashes effect
For people who can have exaggerated effects without wearing false eyelashes, the extra-large and thick bristles can make the roots of the eyelashes be wrapped in a thick paste, producing stunning eyelashes.
Mascara selection tips
Eyelashes are short and thick: Those mascaras that can make eyelashes lengthen and have color are your best choices. Apply mascara to the tip of the eyelashes, so you don’t need to brush the roots of the eyelashes.
Short and sparse eyelashes: For short and sparse eyelashes, the best method recommended here is to choose a lengthened mascara and apply two layers of this mascara on the eyelashes. Apply the first layer only to the roots. After it dries, apply another layer. The second time you apply it, you should cover the entire length of the eyelashes.