Biodegradable and work well.
They are very soft - the bristles are soft.  The head isn't very big, but the softness and size help me get around my back teeth easily.  Most importantly, they are biodegradable!  No more billions of plastic toothbrushes in landfills.  It is nice that there are 4 of them too.  We'll see how well they hold up but seem good so far!
Rating: 5 stars