Omega Seamaster 300M - Nekton or Ceramic?

Omega Seamaster 300M Nekton 210.32.42.20.01.002 42.1mm case 13.5mm thick 49.6mm lug to lug 20mm lug width 300m water resistance Cal. 8806 w/ 55 hours power reserve 114.5 grams $6,400 Omega Seamaster 300M Ceramic 210.92.44.20.01.001 43.8mm case 14.5mm thick 51.3mm lug to lug 21mm lug width 300m water resistance Cal. 8806 w/ 55 hours power reserve 107.7 grams $8,400