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
VK63 mod - looks better than a MoonSwatch in my opinion : r/SeikoMods
Chronograph watch movement VK63 Seiko SII Hattori - Original Seiko Hattori quartz movements
Seiko Mod - Ceramic Rose Seitona Mod on Rubber Strap Seiko VK63 Mechaquartz Movement – Alpine Mods