The Paderno World Cuisine 21 5/8" inch long reusable silicone kitchen strings come in a pack of six. These strings have ridges along the length and have a ring on one end. The "string" is simply tightened to the desired length and then fed through the loop and secured. It is an innovative alternative to traditional cotton twine. The string replaces twine to wrap roasts, fish, rolls and vegetables. It is made of 100-Percent food-grade silicone, withstands temperatures from-76 F. to 446 F., thus adapting to the freezer, traditional oven and microwave. It can even withstand immersion in boiling water. The string is easy to use, durable and hygienic. It does not transmit or absorb odors and is dishwasher-safe. It is also ideal to close food bags. It complies with the FDA. The strings should not be cut.