The Ryobi leaf blower extension is designed to improve the speed and efficiency of your Ryobi 18V Whisper series P21010/P21100 leaf blower. Helps move things a little faster thanks to a narrower tip. Only fits models with the tab at the end of the nozzle. This version has a slot in the back for pressure relief, but the next version is planned to remove the slot and add a slightly raised tab so it doesn't have to move as much to lock.