In a 2x1x2x1 cross, which run end will measure 2?

In a 2x1x2x1 cross, the numbers represent the dimensions of the pipe fittings in terms of diameter or size at each junction. The configuration shows that two of the runs are dimensioned as "2" while the other two runs are dimensioned as "1."

In this context, the term "run end" refers to the ends of the fittings where the pipes are connected. Since the cross has two legs that measure 2 units and two legs that measure 1 unit, there will be two run ends associated with the "2" size. However, regarding the question, it emphasizes that there is a single measurement of "2" at one particular end of the fitting connection.

Therefore, stating that only one run end will measure “2” highlights the distinction that while there are two runs incorporated into the cross fitting, they are separate and do not both participate in the condition of the question being asked. This dimension pattern indicates that, in the context of the cross fittings, we focus on just the measurement at one specified run end at a time. The other ends, although part of the system, do not influence this particular end selection.