They have the same designation as the corresponding 134 series parts (namely, 2..
The incorrectly sized 131s have "1.5" printed on them.
The 133 series are already being released in an 8-pole version, and their counterparts, the 129 series, are also described as having a "2.8" specification.
Here, there seem to be incorrect data in the forum .
/viewtopic.php?t=1583&highlight=part+number+for+pumps*