(1) application: used to calibrate the sound level meters. (2) features: * used the exclusive micro-computer lsi circuit and crystal time base to offer high accuracy measurement & fast measuring time. * wide measuring range & high resolution. * digital display gives exact reading with no guessing or errors. * the use of durable, long lasting components, including a strong, light weight abs-plastic housing assures maintenance free performance for many years, the housing has been carefully shaped to fit comfortably in either hand. it meets requirements of iec651 for type ii sound level meter. model: sound level meter sl-5866 standard: gb/t3785, iec651 type2, ansis1.4type2 function: sl measuring: a .30-130db filter detection characteristics: fast/slow resolution:0.1db accuracy: 1db display: lcd display power supply:1x9v 6f22 battery battery indicator: low battery indicator dimensions: 195x72x31mm weight (not including probe): 195g e－mail：sale@landteknet.com landtek@126.com skype: samantha518 contact person : samantha sun (miss)