Effective fluorescence imaging of Ca2+ signals requires special filters for excitation of FURA 2 in UV at 340 nm and 380 nm. New hardcoated exciters with 8595% transmission for ratio measurements are now available from AHF analysentechnik. Also emission filters with more than 95% transmission will enable maximum of signal intensity. Combining of GFP excitation and FURA 2 imaging can be done as well by using special filter set-ups. These filters can be mounted in all the different cubes of microscopes. The series of new hardcoated filtersets can be found on www.ahf.de on our hitlist of optical filters.