New larger size pack same price **Serene-UM Xtra for dogs over 20kgs can help calm and pacify your pet without the need for tranquilisers. Serene-UM is invaluable for those pets who become anxious or afraid. Serene-UM is also extremely beneficial for showing, training and obedience work helping to calm and relax pets while not causing drowsiness or impairing normal behaviour or performance.