のフタ

the lid of

→ の
phrase Rare #26,673
the lid of の marks what the lid or cover belongs to or is associated with. フタ may be written as ふた or 蓋, and can refer to lids, covers, or sometimes hatches.
JA: 瓶のフタをしっかり閉めてください。
EN: Please close the bottle's lid tightly.

のフタを開けると下水出られる

If you open the floor hatch, you can get out into the sewer.

— REC / レック (2007)

こののフタ取れないんだ

I can't get the lid off this jar.

宗介さんポニョ人間になりたくて魔法のフタを開けてしまいました

Sosuke, Ponyo wanted to become human, so she opened the magic lid.

— 崖の上のポニョ (2008)