The Simplicity Heavy-Duty Silicone Dosing Pump Tubing Combo Pack offers durable tubing designed for reliable dosing performance. With a 4mm inner diameter and 6mm outer diameter, this tubing stays flexible and resistant to cracking, ensuring consistent fluid delivery. The combo pack includes 10 feet of tubing in each of the vibrant colors: green, red, and yellow, providing versatility and ease of identification for different dosing solutions. Whether for freshwater or marine setups, this tubing ensures efficient dosing operations in aquarium systems.