The Seiko C153-5007 is a historically significant calculator watch made in 1977

This is the only one we have found complete with the Seiko Stylus Included !!

amazing condition 

The Seiko C153-5007 is a historically significant, highly collectible vintage digital calculator watch. Introduced by Seiko in 1977, it belongs to the brand's very first generation of LCD calculator timepieces

C153 module was Seiko’s official entry into the calculator watch market when it debuted in late 1977

• Release Year: Late 1977 / 1978.
• Movement: Seiko C153 Quartz LCD.
• Case & Material: Solid stainless steel rectangular/dual-tone case with an integrated 22 mm bracelet.
• Battery Type: Originally utilized a 390 cell; modern replacement standard is a 389 battery.
• Core Functions: Six-digit basic time display (hours, minutes, seconds), calendar (day and date), an internal display "lamp" backlight, and a built-in 8-digit math calculator

• The Stylus Requirement: Because the front-facing calculator buttons are incredibly small, the watch originally shipped with a special metallic stylus tool to press them safely without causing damage. Many secondary market examples missing this stylus are operated gently using a toothpick or a clean pen cap. 
• Time Setting: Time and date configuration is unique for a digital piece; you must pull the physical crown out (like an analogue watch) to flash the digits, adjust them using the pushers, and snap it back in.