This is a used pair of Paradigm woofer model Mini MKii in need of new surrounds.   Being used, they have some minor marks and could a little cleaning.  These may also work for the 3SEMK2 but please check to make sure they will work for you.   Speakers these came out of have a crossover with 3SEMK2 as a model number and like alot of Paradigm speakers, the decal with the model number of the speakers has fallen off the speakers so I am unsure exactly what model these are for.  One measured 3.6 ohms, the other 3.5 ohms.