Here are some key features and characteristics of multistage deep-submersible pumps:

1. Submersible Design: These pumps are designed to be submerged in the fluid they are pumping, typically water or oil. Submersible pumps are more efficient than surface pumps as they push fluid to the surface rather than pulling it from below.

2. Multistage Configuration: Multistage pumps consist of multiple impellers stacked one after another on a common shaft. Each impeller adds more pressure to the fluid, allowing the pump to generate higher discharge pressures. This design is especially beneficial for pumping from deep wells where high pressure is required to overcome the hydrostatic head.

3. High Pressure Capability: Due to the multistage configuration, these pumps can generate significant discharge pressures, making them suitable for pumping fluids from great depths.

4. Efficiency: Multistage pumps are known for their high efficiency, especially at high pressures. This efficiency is crucial in applications where energy consumption and operating costs are significant factors.

5. Corrosion Resistance: Since these pumps are often used in harsh environments such as offshore drilling or corrosive fluid pumping, they are typically constructed with materials that resist corrosion, such as stainless steel or specialized coatings.

6. Reliability and Durability: Deep-submersible pumps are designed for long-term operation in challenging conditions. They are engineered to withstand high pressures, abrasion, and corrosion, ensuring reliable performance over extended periods.

7. Control and Monitoring Systems: Many modern deep-submersible pumps come with advanced control and monitoring systems that allow operators to remotely monitor pump performance, diagnose issues, and optimize operation for maximum efficiency and reliability.