Abstract: I will report a characterization of the NUV Silicon Photomultipliers (SiPMs) developed by Fondazione Bruno Kessler and tested at INFN in Bari (Italy). A dedicated setup has been built in order to measure crucial parameters such as gain, correlated noise and signal – to –noise ratio. The devices tested are SiPMs of different cell size and areas in single or matrix configuration. In particular, I will present last results concerning laboratory tests on the new NUV High Density SiPMs, which are characterised by an increased fill factor respect to the NUV devices.