This is a good example of an early Swan Self Filling Fountain Pen, this is the SF-1 which was made in the UK and dates from around 1930.
The pen is made from Black hard rubber with a chevron chased pattern which is quite worn. The imprint on the barrel and cap is faint but still legible and the pen is in excellent condition overall with no chips or cracks.
The No.1 Fine Oblique Italic nib writes smoothly and gives a lovely shape to your writing. The pen has been fully serviced and is ready to write.