This is a Main Spring Vice. This is a great tool to remove your main spring or frizzen spring from your musket or rifle. I have used this type of vice on a Brown Bess and French Fusil to remove the main spring and frizzen spring. Works better than a pair of vice grips. I keep one in each of my shooting bags just in case I need it in the field. The vice is made of steel and will fit nicely in your pouch. Measures 1 3/4" x 2 1/2