Modified Silicone
Approximately half a tube is needed per Snorkel Vent - perhaps slightly more for a very rough wall.
The item supplied will vary from brand in photograph, but will be an equivalent product.
Please note that we do not advise you to use regular silicone, which is only a sealant. The modified silicone we sell is hi-tack adhesive as well as a sealant. Ideal for bonding Snorkel Vent's to the wall.