1.Bluetooth connection correct steps-(1) download the APP "Print Master" for free, (2) open the APP program, select the correct printer model, label size, (3) connect the mobile phone through the Bluetooth connection function of the APP program, (4) from you Create and quickly print custom labels on your smartphone or tablet (compatible with iOS and Android). 2.The D30 label printer adopts a light and compact design and weighs only 160 grams. The mini pocket label printer can be carried with you. The built-in 1200 mAh rechargeable lithium ion battery can work continuously for 6 hours. You can enjoy smart printing anytime, anywhere. 3.The D30 thermal label printer adopts thermal printing technology and does not require expensive ink or toner. The printing speed of 60mm/s enables easy and fast coding and organization. The high-resolution print quality of 203 dpi ensures a perfect printing experience. 4.The D30 Portable label Maker prints labels with a width of 5mm-15mm, Very suitable for hundreds of tasks in the family or office,Such as archiving, storage and merchandise management.Widely used in home storage, office, supermarket to print labels, price, weight, date, name, etc. 5.Multiple Technical Test- We think highly of our product and do multiple test for our items.