What surfaces do these stickers stick to?

They are standard printed stickers, so they hold best on clean, smooth, dry surfaces such as laptop lids, machine cases, water bottles and notebook covers. Textured or fabric surfaces will not give a firm bond.

Are these stickers waterproof?

Nothing in the product details states a waterproof or weatherproof finish. Treat them as indoor stickers and keep them out of dishwashers and long soaking.

Is this one sticker or a pack?

The listing is for the vintage Singer logo with scrolls sticker design. It does not state a pack count, so assume you are getting the single design shown.

Will it fit on a sewing machine case?

The sticker is die-cut to the logo and scroll outline, so it is sized for small flat areas like a machine case panel or laptop lid. Measure the flat spot before ordering.

Is this an official Singer product?

It is a sticker featuring the vintage Singer logo. The product details do not say it is licensed or made by Singer, so treat it as fan-style merchandise.