The SBDX017 is the final evolution of the original Marinemaster lineage before it was discontinued by Seiko in 2018. The MM300's roots trace back to the legendary Seiko 6159-7999 Professional Diver, one of Seiko's first watches built specifically for saturation divers. 

In the year 2000, Seiko launched the Marinemaster 300, their top of the line diver, with reference SBDX001. It followed in the lineage of the 6159 diver, featuring a robust Monocoque case. The Monocoque case meant that the movement was loaded through the front instead of the back, with one fewer point of water ingress. The case finishing and movement was also elevated, with a beautiful mix of brushed and polished surfaces, with crisp transitions along the edges of the case.

Inside is the 8L35 movement, which is an undecorated Grand Seiko 9S55. This example has been serviced by Seiko, resulting in chronometer level accuracy and 50 hours of power reserve.

The SBDX017 is an updated version of the SBDX001. It has a Dia-Shield coating to protect the surface from scratches, as well as a signed crown. The lume plots are noticeably brighter and greener.

Comes with full set, including original box and papers. Watch is paired with the original bracelet with ratcheting system.