It seems they offer what sells. It's probably not profitable for them to offer the 15 LA in -S form. It's nothing new, and as always anyone that wants one will probably still be able to get the venturi/nva's from tower to convert RC engines. From looking at the Tower website, the 'blue' version is discontinued, but the 'natural' RC 15LA is still listed. The Fox 15 is the BB variety which is really too heavy for any traditional .15 sport/stunt plane. I like .15's even though I haven't built a new 15 size plane in 10 years, and I never could justify the expense of the LA 15. I'd much rather have a FP, or Max-S, etc.