Pex A vs Pex B - What's The Difference?

From a channel Lumen includes in full: HouseImprovements teaches home construction and repair, from framing and drywall to finishing, in long step-by-step walkthroughs of real jobs including a full cabin build.

A 15-minute video from HouseImprovements's catalogue; the title names its topic.

Video by HouseImprovements, played through YouTube's embedded player.