These curved tips are for use with the Smith Little Torch. Tip no. 2 is the finest and can only be used with acetylene. All other tips can be used with either acetylene or propane. Of course, each tip can be set for a variety of flame sizes. Tips 3 thru 7 are included with the Smith Little Torch Kit (see related products below). The Gentec range of torch tips are nearly identical to the Little Torch Tips, are fully interchangeable, and cost substantially less (see related products below).