DVD set containing explanations of theoretical questions and practical applications for hydraulic equipment maintenance technicians. - Title: Hydraulic Equipment Maintenance Technician Volume 1 - Contents: Explanation of theoretical questions, practical application, and practical training - Title: Hydraulic Equipment Maintenance Technician Volume 2 - Contents: Practical application, practical training, and appendices Thank you for viewing. Please refer to the publisher's URL for details. https://www.kyozai.biz/smp/item/SM081.html Used for the national certification exam for hydraulic equipment adjustment. I didn't understand how to solve past exam questions, but after purchasing and studying this DVD, it became easy to understand, and I was able to pass the exam. Please use it to help you pass the certification. *The explanation of theoretical questions is an older version, so there may be differences from the latest version. Due to the nature of the item, returns are not accepted, so please be aware of this.