Washable polyester piping bags
These have certain advantages.Obviously,because they're washable they're reusable.They don't split and burst at inopportune moments and grease from buttercream doesn't seep through the sides. They are used with a connector to which you attach the piping nozzle. This means you can change the piping nozzle without having to set up a new bag. they're also handy for making meringues.