Reducing elbow hoses have different sized openings on each end. They are available in different materials (polyester reinforced- in 3 ply, 4 ply or 5 ply, fluorosilicone lined for fuel and oil etc), finishes (gloss, matte etc) and colors. These reducing elbows are available in various types like 90 degree reducing elbow, 45 degree reducing elbow, 135 degree reducing elbow etc.