1150 – All steel GX cassette
1175 – Also a GX cassette, but with an alu 42t, so a bit lighter.

Can find the 1150 no problem, but 1175 doesn’t seem to be available anywhere…

Anyone happen to know where I can get one?

…. on a complete bike, its OE only.

Ah, that explains it! Thanks for the info – Cheap (relatively) and heavy it is!

Yep SRAM website says it’s OEM only. However, try http://www.gambacicli.com/en/sram-gx-xg-1175-11-speed-cassette.html. They’re offering the 1175 for 123 euros + shipping, which is just slightly more than CRC is charging for the (70g heavier) 1150.
You might be better off with the 1150 anyway as the steel big cog should be a lot tougher. The alloy 42t One-Up big cog on my MTB is showing distinct signs of wear after about 18 months moderate use. MTBs are tough on low gears I guess.
I have a crosser that’s currently 1×10 & I’m planning to put GX on it. A CX bike doesn’t spend nearly as much time in low gears as an MTB so I figure an alloy 42t cog should be OK, but if I upgrade the MTB I’d probably go for the 1150, as robustness is more important than weight on an MTB.

Found that site, but the 123 euros is before VAT – works out around £120 including postage. Managed to get the 1150 for £80 anyway (even less after cashback!), so am happy with that! 🙂 Thanks though!