Use cases
Can be used as a title for subsection on your product page, or as a product attribute description etc.
Setup
Min characters length - Required minimum length of text that.
Max characters length - Maximum length of text that can be entered. If 0 is used there is no limit.

Example Usage
{% assign sub_title = product.metafields.airf.sub_title %}
{% if sub_title and sub_title != ' ' %}
<h2>{{ sub_title }}</h2>
{% endif %}