The 'killer lat superset' is simply a nickname for two kinds of single arm,
high cable lat pulls/rows put together in a single set. The first part of the
'killer lat superset' is a front facing high cable row or lat pull. After a set
number of this movement are performed you transition into a standard single arm
lat pull by positioning your shoulders perpendicularly to the high cable. This
'killer lat superset' is most likely going to be one used towards the end of
your lats workout as it can really isolate the lats and get that burning "pump"
feeling that so many bodybuilders enjoy.