conical centrifuge tube is made of high-purity material, which is durable and not fragile. In order to prevent leakage, we designed a screw cap with a sealing ring, which is longer in length and will not loose. Plastic test tubes is well made, perfectly sized, and has an easy to read black scale, accurate to ± 2, in increments of 1mL (total 15mL). Lab tube includes a convenient white writing sticker for easy labeling and recognition, making it very suitable for scientific experiments and applications. Test tubes with lids are EO sterilized, pyrogen-free, DNase/RNase-free, Max.RCF: 9, 400. It can be autoclaved at 121℃/249.8℉ or Freeze to -80℃/-176℉. Successfully passed 95 KPa pressure test. They are safe to be used in a variety of applications, including solid, liquid, powder, seeds and granular objects. Our centrifuge tubes, which is widely used in the fields of biochemistry and molecular biology, such as the separation and preparation of various biological samples, it is also suitable for handmade, such as beverage and food coloring mixing. It is a good helper for scientists, laboratory technicians, researchers, craftsmen and coffee lovers. size: 50ml / 15ml Material: plastic colour: As Shown Package Contents: 25 x centrifuge tubes / 50 x centrifuge tubes Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing.