Found the ultimate breastmilk freezing trays on amazon! These plastic trays freeze flat and latch so they stay completely closed-- no leaks or bags becoming misshapen if they move! They are fully translucent plastic so easy to wash and just the right size to fit 4 ounce bags of milk. They also stack AFTER being completely latched, making them fit easier in and out of my freezer drawers than the one-piece stacking shelves and ice cube trays I've used in the past. This specific set of 12 is no longer sold but I found a set of 4 that is just slightly deeper (and may actually fit two bags stacked). Even with my oversupply, I find that I usually use 2-3 trays at a time, so the set of 4 would be perfect for most! LTKbaby LTKhome LTKbump