This is an Adjustable Clamp Company Pony and C-Clamp Set. It includes 2- 2", and 2- 1" Pony clamps with plastic booted tips and handles, and 2- 2" C-Clamps. These are considered standard equipment in any photographer's or videographer's grip case.
Pony clamps have a multitude of uses -- holding reflectors, gobos, props, fabric, seamless paper rolls....
The C-Clamps are for clamping together items with more pressure; they have a maximum load of 300 lbs.