This SRAM Rival was released as part of SRAM's first road range, in late 2006. SRAM's own history was entirely as an ATB and leisure brand, so a move into the road market was a big deal. SRAM's initial road range only included the, high-end, SRAM Force and this, mid-range, SRAM Rival. The, very high-end, SRAM Red did not appear until 2007 - I remember seeing it for the first time at the Tour de France Grand Départ in London in July of that year.
This first generation SRAM Rival is a very tidy and surprisingly lightweight unit. Typically for SRAM, it has a composite p-knuckle - something that Shimano would not contemplate at the time. It also features something called 'Exact Actuation'. As I remember it, this is very slightly different (do I mean improved?) from the classic SRAM 1:1 actuation. Whatever the actual geometry, I believe that you have to use Exact Actuation levers with Exact Actuation derailleurs etc. etc. Do I hear the unmistakable gushing sound of profit margins rising?
This example has the following features:
This example has a split in its tension pulley - which is something that I have seen in a number of these derailleurs. Perhaps those glamorous cut-outs introduce unwanted stress-raisers.