ClearSign Technologies Corp (NASDAQ: CLIR) is a combustion technology development company that designs and develops technologies to improve emission performance, energy efficiency, and operational characteristics of industrial and commercial combustion systems. The company has generated no material revenue as of its FY2025 10-K filing (filed 2026-03-31) and has funded operations primarily through equity sales. Its primary product, ClearSign Core, uses a porous ceramic structure or metal flame holder device to reduce flame length and achieve low emissions without external flue gas recirculation or selective catalytic reduction systems. ClearSign pursues an asset-light go-to-market model, relying on manufacturing and distribution partners rather than building its own sales and service infrastructure. Target end markets include upstream oil production, midstream gas processing, downstream refining, institutional and commercial boilers, and chemical and petrochemical industries. The company has a co-branded product line agreement with Zeeco, one of the largest burner manufacturers, announced December 2024, and a collaborative agreement with California Boiler and its subsidiary Rogue Combustion for boiler burner and flare products.

Revenue model

Pre-revenue as of FY2025. Operations funded through equity security sales. Intended future revenue model is product sales through manufacturing and distribution partners under an asset-light structure, with Zeeco handling global manufacturing of ClearSign Core process burners and California Boiler/Rogue Combustion handling boiler burner and flare products.

Products and services

ClearSign Core process burners (co-branded with Zeeco, launched December 2024). Boiler burner systems marketed under Near Zero NOx (NZN), Sub 5ppm NOx (S5), and Sub 9ppm NOx (S9) brand names through Rogue Combustion. Early-stage flame sensor technology for transport applications under development with collaboration partner Narion.

Customers and end markets

Target customers are operators in energy (upstream oil production, midstream gas processing and transportation, downstream refining), institutional and commercial boiler, chemical, and petrochemical industries. Boiler burner customers typically rely on integrated service providers. One unnamed major global customer has expressed interest in the early-stage transport sensor product. No disclosed revenue-generating customers as of the FY2025 filing.

Value-chain role

Technology developer and IP licensor positioned upstream of manufacturing and distribution. ClearSign supplies core combustion technology components integrated into OEM burner bodies. Manufacturing, sales, and customer service are handled by strategic partners including Zeeco and California Boiler/Rogue Combustion.

Geographic exposure

Zeeco agreement covers global manufacturing of ClearSign Core process burners. U.S.-centric regulatory environment cited as a key demand driver. No specific revenue breakdown by geography disclosed in the filing.

Competitors

Zeeco (also a manufacturing partner), Established low and ultra-low NOx burner manufacturers, Selective and non-selective catalytic reduction system providers

Source: SEC 10-K, filed 2026-03-31

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