Crimp neck vials and micro-vials ND8 can be sealed with 8 mm crimp caps, 9 mm PE caps* or 8 mm (2) White silicone/silver aluminium foil, headspace cap. Vials Catalogue v10.indd – Labicom.cz. Crimp top vials provide the best seal of any vials. Crimp septa and solid caps with aluminum or PTFE liners. on the inner diameter of the vial neck.