I set up my PD1644 (Seiko vk63) 15 days ago and still running + - 0 seconds. I'm amazed how accurate this movement is. Is it normal? : r/ChineseWatches
GENUINE JAPAN VK SERIES VK63A VK63 quartz chronograph movement NEW | eBay
Seiko (SII) VK63 Mechaquartz Watch Movement | Caliber Corner
TMI/Hattori SEIKO VK63 Quartz Movement - Sofly
Custom Built using SEIKO VK63 Royal Oak Panda Style Custom Men's Chron – PS Watch Mods
WTS] Custom built watch with Seiko VK63 movement - Speedmaster homage : r/Watchexchange