What is Isabella in the Philippines?

Isabella is the name of a province in the Philippines. The knife you mentioned is a famous traditional handicraft knife made in the Philippines, called butterfly knife. The name of Butterfly Knife comes from barison, a small town of Batangas in the Philippines. The people in this town are famous for producing butterfly knives. According to the old people there, the skill of making this unique knife was passed down from generation to generation by their ancestors.