8-425 HPLC Screw Vials with Caps for WATERS. The Aijiren 8-425 screw cap and vial are suitable for waters and other rotating or robotic arm samplers. The specifications for the 8-425 HPLC sample vial are 12 x 32 mm. The opening of the 8-425 HPLC sample vial is 40% larger than the standard narrow opening vial, preventing syringe problems.