StepVial System Crimp/Snap Vials, SUN-SRi Supplier: Thermo Scientific Vials feature a standard 12 x 32mm profile and are compatible with convenient 11mm snap caps or aluminum seal closures. "Step" design ensures proper centering of limited volume inserts, eliminating missed injections. Vials have a 40% larger opening than standard aluminum seal vials for easier sample filling, and to reduce the chance of bent or broken needles during sampling. Graduated write-on patch for easy filling and identification.