Tri-color optical fiber sub-duct is a communication optical (electrical) cable protective sleeve primarily made of (HDPE), formed through a single extrusion process. It is also known as PE tri-color tube, PE sub-duct, etc. Its features include a long service life, excellent bending performance, smooth inner and outer walls, facilitating easy extraction within corrugated pipes and other main ducts, as well as the threading of optical and electrical cables through the sub-duct, enabling quick construction. The tri-color optical fiber sub-duct is lightweight, high-strength, impact-resistant, corrosion-resistant, and cost-effective; the tube walls are smooth with a low friction coefficient, making cable threading easy and construction efficiency high; it offers good electrical insulation performance, with a service life of up to 50 years, ensuring durability and safe, reliable line operation; the tri-color optical fiber sub-duct can be supplied in coiled form, with long tube sections, few joints, and simple installation; the tubing can be made in various colors for differentiation, with red, yellow, blue, white, and green being the main colors, and custom colors can be produced according to customer requirements.