Put them into water for some minutes， then put them into freezer some hours before you use. More pieces into whisky， the affect will be better. It is washable after use.Whisky Stone Size: about 2x2x2cm (+-0.2cm)1 Set: 9 piecesPacking: 9pcs in a velvet bagAdvantagespared to traditional cube:1. Cool idea， cool gift.2. They look great in the glass.3. Bring a mellow chill to the drink， don`t melt or water down your fine drink flavour.4. The stone edges are rounded， preventing scratching.5. The stones stay at the bottom of the glass.6. The stones don��t add any flavors or smells.Packaging DetailsUnit Type:setPackage Weight:0.200kg (0.44lb.)Package Size:10cm x 10cm x 10cm (3.94in x 3.94in x 3.94in)