Vengeance LPX is the plain-clothes member of Corsair's DDR4 range: an aluminium heatspreader kept deliberately short so it clears the tower coolers that foul taller kits, sold across more speed and capacity permutations than almost anything else on the market. That breadth is the reason it shows up in so many builds, and also the reason two kits with the same name on the box can behave quite differently.
This is the 4×8GB configuration, rated 2666 MT/s CL16. Within this family the timings are what separate the listings — the same 32GB is sold at several speed grades, and the cheaper end of the range is usually a slower bin rather than a different product. Check the XMP profile your board will actually apply before paying for a higher rating.
All DDR4 in this family is unbuffered, non-ECC UDIMM for consumer desktop boards. It will not work in a system that requires registered or ECC memory.