Specification:Withstand temperature: -20~120℃ / -4°F ~ 248°FVials cap material: aluminum, plasticVials stopper material: butyl rubber stopper/silicone stopperVials material: glassVials height: 50mm/2inch Vials entrance diameter: 20mm/0.79inchVials diameter: 22mm / 0.87inchPackage list: 100 pcs 10ml small vials with caps and rubber stopperMaterial: These mini vials are made of solid glass, more resistant to thermal shock (temperature range: -20~120℃ / -4°F ~ 248°F). Comes with a secure-fitting plastic aluminum caps. Equipped with a butyl rubber stopper that is durable, washable, reusable and corrosion-resistant.Good sealing: The equipped aluminum cover and rubber stopper ensure the tightest seal and reduce the possibility of sample evaporation.