The crimp caps are a metal over-seal that is crimped over the top of a stoppered vial. For lyophilized (freeze-dried) products the filling systems partially Trusted solutions – Cromlab. 0.3mL Sci-Vi Crimp Top Vial – GOLD Grade Glass Clear Snap-Cap vials can be used with snap caps or aluminum crimp seal closures. 2-RV. 2-RV(A). 1.5-HRRV.