I happen to have a RadioShack model 64-2193 soldering iron. It's my fault for buying this tip as it is designed for the RS "Dual Heat" soldering iron. Viewed from the ends, they looked exactly like the tip in my soldering gun, so I bought one. How different can they be? The difference is about 1/32 inch. π I couldn't believe that the rounded ends of this "cutting tip" (which goes into the soldering iron) were about 1/32 inch larger than the barrels of my soldering iron. If RadioShack made round-ended soldering gun tips that had such a small difference between models, it's no wonder they went out of business (although it appears someone bought the brand and it exists online now). I've tried all non-destructive methods but I wouldn't fall for it. I figured it would take less time to just drill a 1/32" hole than it would to sharpen it off the rounded ends of a soldering tip. In fact, everything happened pretty quickly, and the new tip fitted in nicely. I used an 11/64" metal drill bit to increase the barrel diameter by about 1/32". The new soldering gun tip is now in place and can be secured with the locking screws. If you decide to do this, make sure you remove the set screws first and make sure you use a good metal drill bit. Thanks to the locking screws, you can continue to use your original soldering gun tip. If you do this, you don't have to worry about voiding your RadioShack warranty. The new cutting tip, like the original rounded tip, gets very hot quickly. I just wish the seller (RadioShack?) would make a little clearer which model numbers of RadioShack soldering irons this attachment is compatible (or incompatible) with. If you have an RS 64-2193 soldering iron (two round barrels with mounting screws and a flashlight), either buy a cutting tip made specifically for this model, or get ready for a little trimming as detailed above. .