The government needs to modernize the education system to equip 21st-century skills that can meet the challenges of the industrial revolution 4.0. The Science, Technology, Engineering, and Mathematics (STEM) approach is one of the recommended learning approaches to help the success of 21st-century skills. In preparing students to acquire 21stcentury skills in the era of the industrial revolution 4.0, teachers need to arrange teaching kits to facilitate learning activities. The STEM teaching kit for heat material through simple technological designs has not been developed, so the researchers took the initiative to develop STEM teaching kit for heat material through simple technology design. This research is part of the development of STEM teaching kit for heat material through simple technology design to enhance design abilities and data literacy. This research aims to determine the feasibility of teaching kits that include syllabus, lesson plans, and student worksheets. The data analysis was descriptive qualitative with the feasibility test of the teaching kit using expert judgment. The results of the feasibility show that the teaching kits developed are feasible and can be implemented in the heat material physics learning activities through a simple technology design using the STEM approach.