Altop industries offers a wide range of pressure calibration products. These are developed keeping in mind modern industry requirements. As part of these products, the company offers digital manometer series apcal 5000/5100. These are specially designed to calibrate the low pressure/differential pressure instruments. They operate on battery and ideally suited for air application. Model apcal 5000 is equipped with 4½ digit display. The accuracy of apcal 500 series is ±0.25% fsd and apcal 5100 is ±0.15%. They are available up to 100 psi and maximum static pressure is 100 psi for 5100 and 2000 mmwc for 5100 and 2000 mmwc for apcal 5000.