Original Seiko leather strap RS05C20BK (20-18) – folding clasp (JDM)

This original Seiko leather strap, model number RS05C20BK, comes from the Japanese Seiko spare parts program and is not regularly available in this version through Seiko Europe . It is a high-quality calf leather strap with a subtle crocodile pattern, designed for classic and higher-end Seiko models.

A key quality feature of this model is the solid stainless steel Seiko folding clasp , which is significantly more elaborate in its construction than a simple pin buckle and contributes substantially to the high price of this bracelet. The folding clasp is an original Seiko, signed and impeccably finished.

The bracelet tapers elegantly from 20 mm at the lugs to 18 mm at the clasp , ensuring a balanced proportion, especially on dressier Seiko models. The top side is black, while the underside is made of natural-colored leather.

The bracelet is equipped with a quick-release system for the spring bars , making it possible to change the strap without tools – a modern detail that is by no means a given with older Seiko original straps.

Delivery includes the original Seiko case with the Japanese Seiko label.

Technical details

• Manufacturer: Seiko
• Model number: RS05C20BK
• Lug width: 20 mm
• Clasp width: 18 mm
• Material: Calfskin (embossed)
• Color: Black
• Clasp: Original Seiko folding clasp, stainless steel, signed
• Spring bars: Quick-change system
• Origin: Japan (JDM)
• Condition: New / NOS
• Packaging: Original Seiko Box