Transdermal is a route of administration wherein active ingredient are delivered across the skin for systemic distribution. It provides a means to sustain drug release as well as reduce the intensity of action and thus reduce the side effects associated with its oral therapy. 4:1 transdermal patch is a topical reservoir patch equivalent to 4 parts CBD/1 part THC or 32 mg of CBD/8 mg of THC with total 40 mg dosage. This patch provides 96 hours of reservoir meaning the patch lasts 3-4 days. Reservoir Patches provide accurate ratios, and larger quantities of available cannabinoids for delivery. Reservoir Patches provide fast and effective delivery of medicine outside the digestive process providing undiluted absorption of cannabinoids into the bloodstream. Hope this helps you gain a better understanding.