Here is a handheld 3D printer that lets you bring your ideas to life fast. The MYNT3D 3D Printing Pen has an adjustable feed to let you control speed and flow. Its temperature is from 130 to 240C. It has an OLED display to let you monitor the temperature.
This 3D pen can use ABS, PLA, and any thermoplastic. It has a replaceable nozzle. It is USB powered and can be used with power banks.