MATERIAL & USE: Made of borosilicate glass 3.3 (linear thermal expansion coefficient (3.3 ± 0.1) x 10-6/K) with a thickness of 2 mm and can withstand temperatures up to 400 °C, a special glass material with low expansion, corrosion-resistant, high-temperature resistant, robust, hard, transparent, and chemically stable. Often used for plant material cultivation, microbial cultivation, and animal cell culture. SIZE: 90 mm. To meet your different needs and applications. Each item contains 5 petri dishes of the same size. Each piece includes an upper lid and a lower dish. The upper lid acts as dust protection. The bottom is flat and the upper lid fits, the work is meticulous, flat, and smooth. WHY CHOOSE US: Unlike disposable plastic petri dishes that can only withstand a maximum temperature of 80 °C, Huanyu's glass petri dishes have a higher temperature resistance of 400 °C. More corrosion-resistant for more chemicals. For laboratory personnel, they are easier to clean and handle. They can be reused multiple times, which is more environmentally friendly and economical. PACKAGING METHOD: Huanyu's packaging department has accumulated experience in global sales, considering all geographical and shipping factors, which shapes our own unique and professional packaging method. Before packaging, our employees check for scratches, burrs, and manufacturing defects. They remove defective items and select only the best quality ones. Our exclusive packaging method minimizes damage during transport. CUSTOMER SERVICE: We are 100% responsible for damages that occur during shipping, because even if we use the most exquisite packaging, some damages may be unavoidable during the transport of glass items. If you find that your petri dish is broken, please be careful not to cut yourself on the glass shards and contact us immediately. Our exclusive customer service will help you solve the problem as soon as possible.