MINITEST 720/730/740 Innovative SIDSP (Probe Internal Digital Signal Processing) technology improves measurement accuracy up to 15mm. F, N or FN probes can be replaced for internal or external probes to automatically identify F(ferromagnetic) or N(non-magnetic) substrates using FN probes. Easy to operate and easy to make mistakes SIDSP technology - the world's latest technology, intelligent digital coating thickness probe