Pure RTV. During the day. Delivered in good condition. It is a thick RTV adhesive/sealant, non-acidic, non-corrosive, suitable for use in and around electronic circuits. It is silicone based so it can contaminate cleaning equipment and interfere with the adhesion of conformal coatings when used to connect parts on circuit board assemblies. Cannot be dyed. Connects almost everything with everything. Flexible binding will not tear. Withstands high temperatures. Excellent stuff. I always have 3145 and 3140 (thin RTV coating) in the store.