Ready assembled crimp closures N 20 and plain crimp caps with no liner. Closures available with a broad variety of septa materials and different cap types / materials, incl. magnetic and bi-metal crimp caps. For all auto samplers transporting vials by a magnet, incl. the CTC PAL autosampler, magnetic or bi-metal crimp closures N 20 should be used (702929, 702834). Aluminium pressure release caps allow controlled release of excess pressure higher than 3 bars. Butyl / PTFE septa for routine analyses; for more demanding analyses and for high temperatures: high purity silicone / PTFE septa. Molded Butyl/PTFE septa with an only centrically laminated PTFE layer for excellent sealing on the glass rims. Pure grey Butyl stopper 702931 for uncritical analyses (e. g. blood). To be crimped with MACHEREY-NAGEL manual / electronic crimping tools N 20.