What is Inner lid vs outer lid?
Where the lid seats.
Short answer
Inner-lid gaskets are cheaper and more widely available.
Inner lid vs outer lid when buying a pressure cooker
Where the lid seats.
Why it matters: Inner-lid cookers are safer and easier to open; outer-lid cookers have a wider mouth for rice and larger volumes.
Look for: Inner-lid gaskets are cheaper and more widely available.
Full Pressure Cooker buying guide