A good post from Moz covering some featured snippet testing they conducted.
Featured snippets are predominantly paragraph snippets, although other formats (list and tables) are increasing.
Here’s a quick takeaway for you:
Key findings: Featured snippet paragraph lengths
The optimal length of a featured snippet paragraph is roughly 40 to 50 words, or around 300 characters.
Lots more to learn here.
btw we discussed this in episode 69 of HubShots last week.