At Urban baits we carefully make our Air-ball pop-ups using a blend of fresh milk proteins. The milk proteins we use give the baits a nice texture and also send out food signals to the carp. The mix is then completed by adding a buoyancy aid to create the pop-up effect. The baits are then rolled and boiled, making them a very attractive hook-bait. Once in the lake they will take on water over a period of time so I would personally tie them on but for shorter sessions piercing them will be fine.