YAW-300B Microcomputer Control Electro-hydraulic Servo Flexural & Compression Testing Machine YAW-300B Computerized Electro-hydraulic Servo-Controlled Flexural & Compression Testing Machine uses fully computer controlled and standard keyboard to input the data. It can automatically save and process the data and automatically print the report. It is constant loading rate (you can freely set the loading rate) and has the automatic overload protection device. It is mainly used to determine the compressive strength and flexural strength of the cement specimen.