What must be marked on cylinders that have passed the External Visual Inspection?

Cylinders that have successfully passed the External Visual Inspection must have specific marks to indicate their compliance with safety regulations. The correct answer includes the Retester Identification Number (RIN), the retest date, and the letter E.

The RIN helps to identify the individual or company responsible for the retesting and ensures accountability for safety. The retest date signifies when the inspection took place and when the next inspection is due, which is crucial for maintaining the safety standards for LP gas cylinders. The presence of the letter E indicates that the cylinder has met the criteria established for its re-certification after inspection.

This marking system is vital for tracking the safety status and inspection history of LP gas cylinders, allowing users and regulatory bodies to make informed decisions about the usage and reliability of the cylinders.