You will find info on your bottle by searching the internet for "vintage banjo bottle" - you will find a number of similarly shaped examples. Some have embossed details, others like yours are plain. These join violin-shaped bottles, popular in the mid 20th century as decorative items. Many had metal hangers so they could be hung on a wall.
Yours, like some others, were sold with an alcoholic product - The "R44" marking is the Rectifier number which can lead you to the bottling company if you can find other examples with intact labels.
