The bell umbilical supplies gas to the bell gas panel, and is separate from the divers' excursion umbilicals, which are connected to the gas panel on the inside of the bell. The bell umbilical is deployed from a large drum or umbilical basket and care is taken to keep the tension in the umbilical low but sufficient to remain near vertical in use and to roll up neatly during recovery, as this reduces the risk of the umbilical snagging on underwater obstructions.