I purchased this one:

waterpik cordless

I like it. It takes 3 AA batteries. It works really well.

I got the WaterPik brand with multiple attachment including one recommended for braces. It was like $30 on amazon, such a life saver!

Found the link:

https://www.amazon.com/gp/aw/d/B071SDS4L7?psc=1&ref=yo_pop_mb_pd_title