Features: Professional Manometer: it can test the differential pressure of areas and pipes, wind velocity of pipeline. It has wide pressure range and +/-0.1% accuracy. Clear Display: 2.7-inch LCD screen with backlight display for easy reading. 12 Selections of Measuring Unit: hpa, kpa, mmHg, psi, mbar, bar, ozin2, inHg, Kgcm2, inH2O, ftH2o, cmH2O. Other Features: Max./Min. value measurement function, data record, data hold and zero function. User-friendly Prompt: low battery indication, Hi and Lo over range indicator. Low Power Consumption & Power Saving: powered by 3pcs AAA batteries(NOT included), and it will automatic power off after no operation for 15 minutes. Compact Size & Lightweight: easy to operate and carry, it also comes with a protective zipper pouch. Wide Applications: applied on chemical industry, electrical industry, nuclear industry to measure the difference of air pressure, etc Specifications: Model: AS511 / AS511B (Optional) AS511: Differential Pressure Measuring Range: -39.98~39.98KPa Maximum Permanent Load Pressure Range: -79.96~79.96KPa Pressure Resolution: 0.01KPa Accuracy: 1%FS, maximum error: 400Pa AS511B: Differential Pressure Measuring Range: -206.8~206.8KPa Maximum Permanent Load Pressure Range: -413.6~413.6KPa Pressure Resolution: 0.1KPa Accuracy: 1%FS, maximum error: 2.08KPa Measurement Selection Rate: 0.5 seconds Unit: hpa, kpa, mmHg, psi, mbar, bar, ozin2, inHg, Kgcm2, inH2O, ftH2o, cmH2O Temperature Measurement Range: -10~60 Humidity Measuring Range: 5~99%RH Temperature Accuracy: 2 Humidity Accuracy: 5%RH Storage Environment: -10~70 / -4~140 Power Supply: 3 * 1.5V AAA battery (NOT included) Material: ABS Item Size: 167 * 65 * 30mm / 6.57 * 2.56 * 1.18in Item Weight: 141g / 4.99oz Package Weight: 305g / 10.77oz Package Size: 24.8 * 9.3 * 5.3cm / 9.76 * 3.66 * 2.09in Package List: 1 * Manometer 1 * Package of Accessory 2 * Plastic Pipe 1 * Zipper Pouch 1 * Manual(English) Shipping: 1.We guarantee to ship goods out within 24-72 hour after payment confirmation except holiday. 2.We ship by China post,HKpost EMS,DHL,Fedex,according to your choice when placing orders . 3.If you didn't receive the item after 45 days,please feel free to contact us.We will make all our effort to resolve the problem. 5. Due to stock status and time differences, we will choose to ship your item from our first available warehouse for fast delivery. Warranty: 1.All items have 1 year guarantee.IF your purchase do not meet merchantable quality, fitness for purpose or match the description, We can make sure your issues are resolved . 2.For wrongly-shipped items, Please contact us in 48 hours after delivery.We will arrange to deliver the correct items or return all your payment. 3.For defective or faulty products,please take photos or videos,we would resend or refund after confirmation.