In version 3.0 new paper sizes were added unfortunately for the default size the page parameters had to be corrected. Before writing a negative review try dimensions 58mm 80mm.
Added the ability to select a graphic printer command (your mobile bluetooth receipt printer most likely supports at least one of them).

App work as print service (standart printing).
It's native printing in apps (GmailWordChrome..) .

You also can easily print texts and images from your phone.
Find menu items "share" "send" or "open" in you app click and select RawBT.
(GalleryFileManager and many other application)

Allow integrated printer with you site and apps!

App site:
rawbt.402d.ru