This Vibrant 4 Ply Reinforced Silicone Straight Hose Coupling is 3.5 inches in inner diameter and 3 inches long. It is made of a strong, durable, and heat-resistant silicone material that is reinforced with four layers of polyester fabric. This hose coupling is black in color and is designed to provide a secure connection between two pieces of hose or tubing. It can withstand temperatures up to 500°F and is ideal for use in high performance engine and turbocharger applications.