Test elements are located inside the storage container which have a test zone on the front side of a transparent pin....http://www.google.com.au/patents/US5609823?utm_source=gb-gplus-sharePatent US5609823 - System for the analysis of sample liquidsAdvanced Patent SearchPublication numberUS5609823 APublication typeGrantApplication numberUS 08/282,149Publication date11 Mar 1997Filing date29 Jul 1994