The present invention generally relates to a device for measuring characteristics of polymeric fluids (semi-dilute and concentrated polymer solutions and melts) in extremely strong elongational flows. In one embodiment, the present invention relates to a device for measuring characteristics of polymeric fluids (semi-dilute and concentrated polymer solutions and melts) in extremely strong elongational flows in spinning jets and/or electrified jets. In another embodiment, the present invention relates to a method for determining the elastic modulus and the relaxation time of a polymeric fluid. Also, the present invention enables one to determine and/or measure the primary parameters needed to describe a viscoelastic material.