[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 free. Gamma radiation The plastic vials have the features of chemically 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 -86C to 121C (Autoclavable, freeze proof and boil proof). Tested to withstand centrifugation of 23,000 in a fully supported rotor. Color: Transparent material: plastic Package Contents: 200 x Sterile 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. The measurement allowed error is +/- 1-3cm.