The clear cap mats are made of silicone rubber, a material that is highly durable to high temperatures, and so can be used to seal storage plates being used for high-temperature storage to protect samples from evaporation. Azenta Life Sciences clear silicone mats are DNase/RNase and pyrogen-free to meet the highest standard of both laboratory experiment and clinical diagnostics. All our clear silicone cap mats are pierceable.