[MATERIAL] These cryovials are made of plastic. Autoclavable. Sample tubes can be repeatedly freeze and thawed [FEATURE] These sterile vials have self-standing bottoms, universal screw threads, and writing area and black graduation mark [WORKING TEMPERATURE] Vials are autoclavable to 121℃ and freezable to -86℃ [STERILE] These vials with caps are DNase & RNase free, and human DNA free. Gamma radiation sterilized The plastic vials have the features of chemically resistant to alcohols and mild organic solvents. Besides, transparent wall permits easy viewing of tube contents, and brown wall reduces UV light transmissions to protect photosensitive contents. Last but not least, the small vials are stable from -86ºC to 121ºC (Autoclavable, freeze proof and boil proof). Tested to withstand centrifugation of 23,000 RCF in a fully supported rotor. Color: Transparent material: plastic Package Contents: 200 x Sterile Tubes