Silicone watches first became popular in the 70s, when people realized that plastic was kind of fantastic 'it's durable and has a futuristic finish. Silicone is also much cleaner than leather straps, which can go moldy, or metal that needs to get cleaned regularly, so brand's including Swatch and Lacoste quickly caught on. Now you can find silicone designs in pretty much every color of the rainbow, meaning it's perfectly acceptable to collect them all.