which Y pipe correct for me??

[wafi]

I have escalade 2007 & I order kook headers part no. 6753 & magnaflow cat back part no.16671 from summit.


now I'm looking for Y pipe & they have 2 diffrent part number with out converters & I'm confuase which one correct for me or which is the difrrent between this 2 y pipes
part no.6754-OC-62LS &
part no.6754-OC-62

any one can advice me please??