This is the best spring clamp that money can buy.  Will likely outlast all of us.  Comes in a film crew's favorite color, black.  

Black rubber tips prevent damage to material. 

Clip mouth opens up to 3 5/16" inches wide.

Great for plastic, fabric, and glueing work on wood and metal. Also used for securing plastic sheeting, tarpaulins, covers, fabrics, and photographic backdrops.