The sound through the pipe accentuates what they hear and they are more cognizant of how they are pronouncing. It really helps some children hear the vowel sounds that they are making.
The kids love using them and are excited to reread a book or poem while they "listen" to themselves read. They only have to read at a very low volume to hear themselves, so several children reading at the same time is not a problem.
When we are revising writing, I have the students read their writing quietly to themselves (usually sitting at an area like a writing center) and then go back and read it a second time using a blue pen to make changes. Sometimes they are reading for flow, sometimes with a purpose, such as adding strong verbs or similes and metaphors.
The piping is inexpensive and can be decorated with puffy paint, stickers, or names written in Sharpie (it wipes off with rubbing alcohol at the end of the year). It's a fun tool to have in the classroom.
