The strap size depends on the reference. Yours is engraved on the case back or between the lugs at 6 o'clock.
18 or 19 mm
Verification: From our database, not yet verified
37 to 39 mm cases · 1998 to 2012
Indicative information. Check your watch before buying a strap: whatsmylugwidth.com is not responsible for an incorrect size.
Grand Seiko JDM Mechanical references in our database. Each card says where its width comes from: listed by the maker (linked to the maker's page in the details), two independent sources agree, or listed in our database and not yet verified by us.
JDM Mechanical 4S15
Lug width: 19 mm
Source: DatabaseCase size: 37 mmYear: 1998Silver dialCase material: Steel
JDM Mechanical 4S35
Lug width: 19 mm
Source: DatabaseCase size: 37 mmYear: 1999Black dialCase material: Steel
JDM Mechanical Hi-Beat
Lug width: 18 mm
Source: DatabaseCase size: 39 mmYear: 2012White dialCase material: Steel
No reference matches.
Grand Seiko JDM Mechanical lug width: 18 or 19 mm depending on the reference. The most common is 19 mm (2 of the 3 references with a listed width in our database). Find your exact reference in the table below. These widths come from our database and are not yet verified.
No. 2 different lug widths appear across the line, often by case size or generation. Check the reference engraved on the case back or between the lugs.
From our database, which lists 3 Grand Seiko JDM Mechanical references, 3 of them with a listed width. Each reference card says whether the maker lists the width, two independent sources agree on it, or it is not yet verified.
The gap between the two lugs that hold the strap, in millimetres. A new strap must match it exactly: 20 mm lugs take a 20 mm strap.
Most watches use spring bars, so any strap of the right width fits. Many smartwatches use their own band system instead, such as Apple Watch bands or Garmin QuickFit.