Tubes with round bottoms are manufactured from ASTM E438 Type 1 Class A Borosilicate 3.3 glass. Includes polypropylene autoclavable screw cap with PTFE liner. Additional Info: Culture Tubes With Cap, Round Bottom, 5ml Package Size(L x W x H): 4 X 2 X 3 (IN) Categories: Culture Tubes, Glass HTS Code: 7017.90.5000 UNSPSC: 4.11217e+007 Country Of Origin: INDIA