If you can extend the travel (not all models can be extended) you dont need any parts all you need to do is a service on the forks and whilst you have the forks apart you remove an Alltravel reducer
http://www.sram.com/_media/techdocs/95-4310-755-000%202006%20Recon%20Service%20Guide.pdfThis is the manual for the 2006 model but all the Rockshox forks I have worked on are pretty similar. Have a look on page 5 of the pdf for a drawing of what your looking for.