貝 is one of the most commonly used Japanese kanji, and it also has a lot of special readings in addition to the standard onyomi and kunyomi readings.
ONYOMI 音読み
かい kai
KUNYOMI 訓読み
バイ bai
Examples
私が手にしてるのは貝の化石です。What I have in my hand is a fossil seashell.貝は好きではない。I don’t like shellfish.砂浜でいろんな貝を拾うのは実に楽しい。It is a lot of fun picking various shells on the sands.火力とお鍋と貝の種類によるわ。It depends on the strength of the flame, the pan used and the type of ingredients.