E3H 1000 PR121/P-LSIG IN=1000A 4P F HR

This appears to be a product or model identifier. Here's a possible breakdown:

• E3H: This could represent the manufacturer, product line, or a specific series.
• 1000: This might indicate a size, capacity, or model number.
• PR121/P-LSIG: This likely refers to a specific product variant or configuration.
• IN=1000A: This could denote an input specification, such as current rating or voltage.
• 4P: This might stand for "four poles," referring to a type of electrical connection.
• F HR: This could be a combination of letters representing features, certifications, or regulatory compliance.