Halma PLC is a provider of security services. The company operates four segments: process safety, infrastructure safety, medical, and environmental and analysis. The segments by revenue, infrastructure safety and medical, offer products that detect hazards to protect assets and people in public spaces, transportation, and commercial buildings, as well as products that assess eye health and assist in eye surgery. The other segments provide systems that detect hazardous and flammable gases and monitor corrosion at the workplace, as well as water network products and opto-electronic technology. The end markets are the United States of America and Europe.