The Seiko 3Y03-0B20 is a watch model based on the 3Y03 movement.
Parts List
| 200W28HN01 | crystal |
| 200W28HN | crystal |
| 35MF6NS1 | crown |
| 35MF6NA1 | crown |
| FH2081B0A | case back gasket - case back gasket |
| EA0040B0 | case back gasket |
| 86581380 | crystal gasket |
| 86581381 | crystal gasket - plastic gasket for crystal |
| 86179080 | bezel gasket - plastic gasket for bezel |
| Z5379C-LKG | band - link |
| Z5379J-LKS | band - link |
| Z5379L | band - metal band |
| Z5379L-LKG | band - link |
| Z5379S-LKS | band - link |
| Z5379S | band |
| Z5379J | band |
| Z5379C | band |
| Z5379S-PB1 | clasp - parts for buckle/clasp |
| Z5379L-PB1 | clasp - parts for buckle/clasp |
| Z5379S-BK1S | clasp - clasp |
| Z5379C-BK1S | clasp - clasp |
| Z5379L-BK1S | clasp - clasp |
| Z5379J-PB1 | clasp - parts for buckle/clasp |
| Z5379C-PB1 | clasp - parts for buckle/clasp |
| Z5379J-BK1S | clasp - clasp |
| 08SC16AG | others - second hand |
| 0351546 | others - winding stem |
| 81180229 | others - bracelet fixing pipe |
| 81604259 | others - bracelet fixing pin |
| 0801752 | others - date dial |
| 0866553 | others - holding ring for dial |
| 3Y030B20 | others - case back |
| 3Y030B2061 | others - case |
| 3Y030B2061Z | others - case |
| 3Y030B2098 | others - case |
| 3Y030B2098Z | others - case |
| 3Y030B9LXS13 | others - dial |
| 3Y030B9WXS13 | others - dial |
| 3Y030C0LXS14 | others - dial |
| 3Y030C0WXS14 | others - dial |
| 3Y037 | others - machine code |
| 82352681 | others - bezel |
| 82352689 | others - bezel |
| 82801600 | others - case ring |
| EA0040B0A | others - crown and stem gasket |
| 08SC16ES | others - second hand |
| 2BB080L2BKC | others - minute hand |
| 07TG0MGM | others - minute hand |
| 08TJ2MSM | others - minute hand |
| 08TJ2MSH | others - hour hand |
| 07TG0MGH | others - hour hand |