Cal. 8L55 is a Hi-Beat automatic movement used in the Seiko Prospex SLA025/SBEX001 dive watch. It is a variant of the Grand Seiko 9S85 movement with simpler finishing and adjusted to a lower standard of accuracy. The movement was used in a few rare Prospex dive watches from 2015 through 2019 but is best known for powering the limited edition Prospex SLA025, a re-creation of the 1968 6159-7001 which won the prestigious GPHG award in the Dive Watch category in 2018.
- 2015-2016 Seiko Prospex SLA025/SBEX001 Hi-Beat Diver (LE of 700 pieces)
- 2018 Seiko Prospex Marinemaster Professional SBEX005
- 2018 Seiko Prospex Diver 300m Hi-Beat Ref. SLA025 (LE of 1,500 pieces)