b1 is a french press/press pot/coffee press/coffee plunger/cafetière/сafetière à piston for filtrated liquid b2=j2 [default: coffee] with filter j1 prohibiting passage of solids j3=d2 pressed by force d1, container made of material b3 with lid b4.
See also: making coffee (=kafpra), coffeemaker (=kafpraca'a), coffee (paper) filter (=kafpleju'e).