Oral-B interdental brush

I usually use interdental brushes. I typically use Daiso products, but this is my first time trying an Oral-B interdental brush, and I think it's pretty good.

That core-like part seems to be both hard and flexible.

The handle is also flat, but it is surprisingly comfortable.

It is a bit thin, so it bends easily; this could be perceived as both an advantage of flexibility and a disadvantage of being weak.

Since they said it's okay to reuse it, I'm going to try to use it sparingly.