Can you please help identify?

Hi, I’ve had this ballpoint(?) pen for decades and am looking for a refill replacement. The logo is a circled “51” with wings, so I suspect it’s a Retro 51 pen but I really don’t know. It was bought for me as a gift at Kate’s Paperie in NYC back in the 1990s.

Any help identifying it and a refill cartridge would be very appreciated!