The Proshield is a spectra - Spectra is just the lens used. JT do the elite lenses in their low end/site gear, spectra, used in flexes, proshields, Proflex, and those weird chamelion things they did for a week or two, and now the qls, quick change system used in the new reapers.
as has been said... these ar a set of JT Spectra ProShield Mask. ALL Jt Spectra parts, ie Frames, Flex faceplates, soft ears, and straps will fit this mask, so you can easily cusomise it, should you wish to.
The spectra isnt used in the new qls range - the spectra range is a thermal 260 lense that has been the basis for all of JT high end goggles for a very long time now and like Gurkha has said any of the JT range like the eps parts etc will fit the Spectra Frame.
The QLS uses a new lense system with 270 degres vision and a quick lock/release system.
Sorry, re-reading what I wrote it left room for confusion - I meant they had three - Elite, Spectra "and now, QLS"! Oh and the weird chamelion thing, I found out is called a Proteus.