Abstract: A thermometer sheath in a multiple pack comprising a continuous support foil (1) of paper on which a lower and an upper plastic foil (2 and 3) are placed, whereby the plastic foils (2, 3) are welded together and the lower plastic foil (2) is releasably attached to the support foil (1) by means of a heat sealing line (4), which delimits a number of case-shaped thermometer sheaths closed at one end, which are detachable from each other and from the support foil (1), and whereby the lower plastic foil (2) is longer than the upper plastic foil (3) thus that a flap is formed at the case orifice. A stiffening strip (5) of plastic material is positioned between the upper and the lower plastic foil (2 and 3) transversally to the longitudinal direction of the case and attached to said plastic foils (2, 3) by two opposite parts (4',4") of the heat-sealing line (4), whereby the stiffening strip (5) extends beyond the end of the upper plastic foil (3).