RS4b- I bought them new in 1986 at Anderson AFB Guam and hauled them all over the world with me. I replaced the woofer foam in 2005, had new crossovers made a couple years ago, and built new bases. latest "upgrade" was to apply 1/4" closed cell foam around the mids/tweeters (like on the RS IIIb). They sound better than ever.












