After many discussions with yarn suppliers We have been able to find a PVA yarn that fully dissolves in all waters and can be used all year round. The Spun PVA is a new yarn that we have added to our range.The PVA Yarn will try to shrink into a very tight tube when put into the water.When your bait is inside it will try to shrink into the tight tube but will be unable to do this.The water then works on it until your bag explodes.