This is the stock fuel feed hose that connects directly to the tank sending unit, is about 10 inches long, and connects to the long feed line that runs up under the car.
This hose can often get corroded or damaged from trying to remove it to either drop the fuel tank or remove the fuel sending unit.
This line MUST be disconnected if you are going to remove the fuel tank or even just the sending unit. It is MUCH easier to disconnect the line from where it mates to the hard line rather than at the sending unit - you have more room to work and get tools to separate the lines. (Alternatively, since you are replacing the line, you can simply CUT the soft line so it is easier to remove.) Once the short line is separate at the junction pictured below, then you can remove the sending unit and line together and then separate the line from the sending unit on a work table.
We DO have an aftermarket and more affordable alternative Custom Tank to Hard Feed Line replacement for this line.