Use with any Standard Camping-style Propane Tank. Completely Reusable and is a great substitute for Green Gas. Silicone oil container: Store silicon oil and lube your GBB with refill propane. Non-leaking design: The silicone oil will mix up with the propane while not use. The silicone oil will not leak out from stem. Mixed propane with silicone oil: Only when you press the stem, the silicon oil will go out with propane and go inside to your GBB magazine. For Airsoft use ONLY. Add 3 drops of silicone oil into oil port before fill. Do NOT use WD-40 as a substitute for silicone. Note: If it is leaking, it should be no sealed. At the position of the internal rubber ring of the adapter, you can apply a layer of silicone oil to seal.