Thanks to David for providing these. I use them in my middle school Technical Applications class for a few reasons: 1. They are elementary school kid proof - if they break, I just print a new one. 2. They don't destroy the objects the vices hold and 3. It costs less than $3.00 to make each.
One of the best tools to have in middle school. Especially when the district does not want to spend money on material tools.