Slave switches for Leviton VRS05?

Does anyone know which switch will work as a slave for the Leviton VRS05-1LZ. I have a 4 way setup. Thanks!

http://levitoncompanyinc.com/OA_HTML/ProductDetail.jsp?partnumber=VRS05-1LZ&section=44141&minisite=10251

Notes: Use VRCS1-1L, VP0SR-10 or VP0SR-1L for 3-way applications

Thanks for the info!