Gland packing is a flexible, soft material used to create a seal around a shaft or valve stem to control fluid loss and ensure the proper operation of mechanical equipment. It's a traditional method of sealing that's still popular today, particularly for handling corrosive fluids. 

Here are some characteristics of gland packing: 

• Material: Gland packing is made from a braided or twisted material, such as graphite, PTFE, or aramid fibers. 
• Function: Gland packing is a heat-resistant, anti-friction seal that's used in rotary equipment like pumps and steam valves. 
• Installation: Gland packing is easy to install and cost-effective. 
• Selection: Gland packings come in different sizes to accommodate different shaft diameters and stuffing box dimensions. The right sealing material and mounting are important for reliability and economical efficiency. 
• Maintenance: Some leakage from the gland is normal to ensure adequate lubrication and cool running. 
• Wear and tear: Gland packing signals wear and tear by increasing leakage.