4-6lb Curetube has an Easy Burping Lid designed to easily open/close tube. External Hygrometer allows the user to know the humidity in the tube without having to open. Interior lining is designed to keep humidity in/out. Dry Erase board for easy organization and note taking. The humidity/oxygen slot is for placing a humidity pack or oxygen pouch into the slot. The CureTube is designed to be placed horizontally on its side. To meet your curing and storage needs.