Lutron sound level meter has 3 range selector i.e. 30 to 80 db, 50 to 100 db, 80 to 130 db with 50 db on each step over/under range indicating.Its measurement range is a weighting- 3 ranges, 30 to 130 db and c weighting- 3 ranges, 30 to 130 db features:Large lcd display, easy to read, time weighting and frequency weighting meet, iec 61672 type 2, external calibration vr, condenser microphone for high accuracy and long-term stability, max. Hold function for stored the maximum value, warning indicator for over and under load, lcd display for low power consumption and clear read-out even in bright ambient light condition, used the durable, long-lasting components, including a strong, light weight abs-plastic housing case, pocket and light weight design allow one hand operation.