A Pack of 30 Black and Gold coloured heat shrinkable caps (approx contents) for adding that "finishing touch" to your home made wine. Simply place over the neck of the bottle and apply heat, either from a heat gun, a hairdryer or the steam from a kettle to cause the cap to shrink and form a tight seal. Because of high light levels when I was photographing these caps, they appear to be almost Royal Blue. They are in fact black when viewed under normal light conditions.
Using an electric kettle is probably not a good idea as you will need to constantly over-ride the safety cut off and can cause damage to your kettle. Using a hairdryer or craft heat gun is probably the best and safest way to apply these caps.