BTW, I noticed on my Creavy receipt they follow all dimensions with “ID” to make it clear this is an inside dimension.  So, when referencing the o-ring dimensions, I would recommend we follow their nomenclature so that others (new to the list) will not be misled into thinking we’re referring to CL measurements

FWIW Guys,

 In the regular engineering world o-rings are always refered to by their ID. Parker is the industry standard in the US and most of the other manufacturers even use the same numbering system. The odd part is that the CROSS SECTIONAL diameter is usually LARGER than listed, just to make it wierder.

Bill Jepson