CK Precise Plastic Tips are made from a high quality plastic which will not bend out of shape. They fit most standard couplers, are dishwasher safe, don't rust, and are resistant to food stains. Because the plastic tips float, they are less likely to go down the drain or get into garbage disposals. If you use these tips when working with candy coating, you will find the candy does not set up as quickly as it does in a metal tip. If it does set up, just microwave a few seconds to warm. These plastic tips have been tested and used by expert cake decorators.