There are several different types of silicone moulded ear plugs. They can be divided into three types.
1) Remoldable soft silicone ear plugs. These are often used for swimming as their stickiness creates a seal which keeps water out. Unfortunately they can be messy and bits sometimes break off and get left behind in the ear canal. These need to be removed by an experienced doctor. This type of plug remains soft and putty-like, it doesn't harden.
2) Professionally moulded silicone ear plugs. These are made by an audiologist in their clinic. They tend to be comfortable and effective at keeping water and sound out. Unfortunately they also are expensive, often costing £90 or more. This puts many people off. If they don't fit well then new ones need to be made. This can be expensive and take a long time.
3) Silicone molded ear plugs from a kit. These are usually provided as a two-part mixture which you combine in your hands. These cost less than visiting the audiologist but are messy and leave residue on the hands. If you don't get it right first time you are left with a pair of plugs which don't fit. The only alternative is to buy another kit.
Thermoplastic is a much better alternative to silicone. ZenPlugs use a unique mixture which softens in hot water. It doesn't leave messy residue and isn't sticky when you use it. It can be remolded as many times as you like meaning that if they don't fit perfectly the first time you get to practise as many times as you need. This is unlike the silicon plugs which can't be softened again once they have set.
Because ZenPlugs can be made at home from a kit they cost far less than having the audiologist make them for you.
Summary. There are three types of silicone moulded ear plugs. Soft silicone, moulded silicone ear plug kits and silicone plugs from the audiologist. ZenPlugs are made from thermoplastic which costs less, is less messy and can be remolded as many times as you like.
Dr Toby Bateson