Red Pulse is one of the three skins released under The Red Planet part of the Last Master offer. It could be purchased as part of an item deal in late December 2017.
Red Pulse could be purchased for $19.99 in the limited time "Best Deal!" which included the Elite Pilot skin and 1800 DNA. It was not available for individual purchase and may not be available for purchase in the future.
Details of this skin may vary depending on location, platform or time.
Note: The Red Planet sub-offer was released again for a limited time in mid January 2021. This time Red Pulse, Elite Pilot and 2300 DNA could be purchased for $9.99