Sequential shulker unloader
Definition
A sequential shulker unloader is a device which filters out one type of items from a mixed box, then it breaks the box when it runs out of that item type and sends it to the next slice (if tiled). SSU's work by putting a shulker box over an item filter, the filter hopper will naturally only pull out items which match the item type anywhere in the box, the rest of the items stay in the box. This is useful because if you just want one one or few item types, its faster to use an SSU than: unloading the entire box, filtering the items, and then loading the remaining items back in. Some SSU designs are tileable so you can unload different item types in each slice. Boxes with leftover items travel through each slice sequentially (this is where the word "sequential" comes from). A variable SSU which sets its filters dynamically is called a cycvar.