Simply run a bath, drop your cauldron in and watch it fizz... The cauldron is approximately 63mm in size.
They each weigh 150g 
including the cauldron.
Vegan Friendly, Gentle To Skin, Cruelty Free
Made In Lancashire
Witch's Ghastly Green Cauldron Bath Bomb
Ingredients: Sodium Bicarbonate, Citric Acid, Parfum, CI19140, CI42090
Not to be swallowed/avoid contact with eyes, not suitable for under 36 months due to small parts and the risk of choking.
Use within 12 months of opening