The main characteristic of this plate variety is a break in the outer frame line under the second to last A of CATARATAS. I show here only two of the 5p1L1 specimens. By how commonly I find this plate variety, I am postulating that it is a master plate variety. In addition, other flaws vary from stamp to stamp.
Here is a 5p1L2 specimen with the same lower line break but with different additional flaws.
Notice that the break appears in the same place for one of the 5p1L1 stamps and a 5p1L2 stamp. The 5p1L2 is the remarkable 'long scratch in background' plate variety.