It's not a stamp that you stick on. It's a stamp that you press
Not a postage stamp, a rubber/wood stamp
切手=stamp
スタンプ=stamp
a stamp that you stick on・a postage stamp
貼る切手
a stamp that you press・an ink stamp・a rubber stamp・a wodden rubber stamp
押す(インク)切手
it's not a 〇〇. It's a ~
Not a 〇〇, a ~
〇〇じゃなくて、〜だよ
ご参考になれば幸いです。