The Parker Royal Challengers have some of the most attractive celluloids, alternating herringbone and marble strips down the length of the cap and barrel. The Royal Challenger button filler was released with a sword clip and with this stepped spade clip.
There are pens with three cap bands and this more ornate cap band. Some have visulated sections and some like this one have plain black sections. They don't show in the 1937 or 1938 catalog, but a price supplement shows the pen came in standard and slender sizes in brown, burgundy and grey for $5.00 and the matching pencil for $2.50.