Identifying H6 O2 sensors

Hi guys,

I’m new to the forum, but have had a good few Subarus over the years, from a good few L series through Gen 1 Legacy, Gen 3 and 4. I’ve recently bought a pretty decent 2006 H6 Outback with 98,000 miles on it. It’s just lit it’s management and traction lights - car drives just fine, no limp home mode. Code recorded is H02S bank 1, sensor 1 - I’m just about to order a new O2 sensor - but need to know which sensor to change - and any suggestions of where to get it from?  

Any intel, suggestions etc, gratefully received. 

With best regards

Andy H