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Exhibit 99.1 ClearSign ClearSign Technologies Corporation Provides First Quarter 2021 Update SEATTLE , June 15 , 2021 -- ClearSign Technologies Corporation ( Nasdaq : CLIR ) ( " ClearSign " or the " Company " ) , an emerging leader in industrial combustion and sensing technologies that improve energy , operational efficiency and safety while dramatically reducing emissions , today provides an update on operations for the first quarter ended on March 31 , 2021 . " During the first quarter of 2021 , we continued to move strategic projects forward , to install more of our products in the field , and with the addition of completing our first performance test for a supermajor and our field installations performing well , we believe the industry at large is starting to accept our best in class technologies as mainstream . The conversations and partnerships that we are developing give us confidence that we are executing on our commercialization plan , ” concluded Dr. Deller . Recent strategic and operational highlights during and subsequent to the first quarter 2021 include : Conducted Performance Demonstration for Supermajor for installation on European Project : Successfully set up and completed the formal demonstration of the burner for our European supermajor project . This formal witness performance test was completed on June 11th . Following standard procedure , the data is being reviewed by the customer and installation is expected to occur later this year . This is the first purchase from this customer and the second super major customer for the Company . This order was previously announced on Feb. 2 , 2021 . Successfully Installed a Multi - Unit Process Burner Order for Major Energy Infrastructure Company : The installation is made up of three burners in an existing process heater at a California storage and transportation terminal . The burners were sold by ClearSign's channel affiliate , California Boiler , who were a subcontractor to the overall project management company , R. A. Nichols Engineering . The Company is awaiting third party emissions confirmation report . Completed the Performance Testing and Application for Firetube Boiler Burner Certification in China and subsequently received certification : With this certification , the Company can produce , market and sell its 125hp fire tube boiler burners throughout China . Signed a Collaboration Framework Agreement ( CFA ) with Jiangsu Shuang Liang Boiler Co. Ltd : The Company signed a non - binding CFA agreement with Jiangsu Shuang Liang Boiler Co. Ltd , the largest fire tube boiler manufacturer in China , to provide a next generation ultra - low emission , and high efficiency integrated boiler burner package for the Chinese market . Entered into an Agreement with California Boiler for Sale and Installation of 2.5 ppm NOx Capable Ultra - Low Emission Boiler Burners and Low Emission Flares : The agreement is for the sale and installation of " ClearSign Core ™ M " enabled ultra - low NOx combustion equipment into the U.S. market . Both companies will be responsible for sales , California Boiler will be responsible for installation and the provision of controls , and ClearSign will provide the technology and product design . Currently , the Company is awaiting delivery of a newly fabricated 125hp ClearSign Core fire tube boiler burner . A 500hp burner is being fabricated as well and both will be installed in rental boilers for customer demonstrations .