Marty Mcfly Casio CA-50, Common to popular belief the CA-50 was the original Casio worn by Marty Mcfly, before he wore the CA-53 in the later scenes! This is mine I sourced
Amazon.com: Casio General Men's Watches Data Bank CA-506-1UW - WW : Casio: Clothing, Shoes & Jewelry
Casio] let me flex my CA-50 before the Casio flex wave is over! : r/Watches
Vintage Casio CA-50 (437) Japan RK Back To The Future Digital Calculator Watch | eBay
Casio CA-50 Calculator Watch Module 437 Back to the Future - Etsy Hong Kong
Casio CA-50 Calculator Watch Module 437 Vintage Back to the - Etsy Denmark