Group 1 - The stock price of Blue Shield Optoelectronics closed at 27.50 yuan on August 19, 2025, down 1.36% from the previous trading day [1] - The company recorded a trading volume of 103,668 lots, with a total transaction amount of 287 million yuan on the same day [1] - Blue Shield Optoelectronics specializes in the research, production, and sales of optoelectronic measurement instruments, primarily used in environmental monitoring, meteorological observation, and industrial process control [1] Group 2 - On August 19, 2025, Blue Shield Optoelectronics executed six block trades totaling 520,000 shares, with a transaction amount of 13.01 million yuan and an average transaction price of 25.03 yuan, representing an 8.98% discount to the closing price [1] - Institutional accounts purchased 120,000 shares, amounting to 3.00 million yuan [1] - The net outflow of main funds for Blue Shield Optoelectronics on August 19 was 16.28 million yuan, with a cumulative net outflow of 36.12 million yuan over the past five days [1]