>>12566944I don't know its name in english, but here we all it "the woodpecker"
you put on a reagent bottle, tip it over to fill the bulb and then you tip it over to the other side to get given volume out that fits inside the bulb
it's not particularly accurate, but it is a fast way to pour out some kind of reagent you can add in excess into many flasks
the hook is just for better grip - a place to put your finger when holding it
