GE Silicone 2 sealant is what’s called a “neutral cure” silicone, which means no acids are released during the curing process (as there are in GE Silicone 1 sealant). This enables GE Silicone 2 sealant to adhere to a broader range of substrates such as plastics, concrete, and high-end metal finishes such as brass and copper. Also, the odor of a neutral cure silicone such as GE Silicone 2 sealant is much less pronounced than an acid or acetoxy cure silicone such as GE Silicone 1 sealant.