Seiko revolutionised the dive strap with the introduction of vents that allow the strap to change size and remain tight as the water pressure increases. This game changing strap was the XGL-801 that was introduced with the 6159-7010 “Grandfather Tuna” but before this Seiko had released a number of different dive straps.
In 1965 Seiko released their first diver the 62MAS (6217-8000) and it was provided on a third party Tropic branded strap. Tropic was a very well known dive strap manufacturer at the time and numerous companies used their straps. More details on the original strap for the 62MAS can be found here - 62MAS (6217-8000) Original Tropic Strap.
For their second model of diver, released in 1967, Seiko produced their own strap the ZLM01 a.k.a. “Waffle” strap. With a distinctive pattern reminiscent to a waffle iron plate, the strap was provided on the 6215-7000 and later on the early 6159-7000 and 6105-8000 models. More information on the ZLM01 Waffle strap can be found here - First Seiko Dive Strap - ZLM01 Waffle.
Following up the waffle was a new strap released two years later in 1969, the Chocolate Bar. This strap does not have a known part number but is named after the distinctive pattern on the top surface. This was provided on both the 6159-7000 and 6105-8110 models. More details on the Chocolate Bar strap can be found here - Second Seiko Dive Strap - Chocolate Bar.
Released in 1972 the third Seiko designed dive strap was the XGL-731 a.k.a. “Tire Tread”. This was only ever provided on the 6105-8110 in the Japanese market and was produced until the end of the models life. More info on the XGL-731 can be found here - Third Seiko Dive Strap - XGL-731.
In 1972 Seiko released a Watchband Catalog that detailed three dive straps. The first is the Chocolate bar strap, the second the XGL-731 and the third a previously unknown model. This final strap D-3 was the cheapest of all three at ¥700, was sized at 19mm and was available in three different colors, black, orange and blue. If anyone has an example of this strap or any additional information please let me know.
The flat designs of these straps were replaced by the vented design of the XGL-801 that was introduced with the 6159-7010 “Grandfather Tuna” model. Since that time all of the Professional Seiko dive straps have featured some kind of vent, either straight, curved or even a wave design. This type of compression vent is now a standard feature on most dive watch straps from all manufacturers.
Summary of Early Seiko Dive Straps
|Model||a.k.a.||JDM Release||JDM Models|
|Tropic||Tropic||1965 - 1968||6217-8000 (62MAS 010)|
|ZML01||Waffle||1967 - 1971||6215-7000 (6215 010), 6159-7000/1 (6159 010), 6105-8000 (61MC 010)|
|N/A||Chocolate Bar||1969 - 1972||6159-7001 (6159 010, 6159 011), 6105-8110 (61MC 022)|
|XGL 731||Tire Tread||1972 - 1977||6105-8110 (61MC 022, YAH028)|
|XGL 801||Grandfather Tuna strap||1975 - 1979||6159-7010 (YAQ028)|