Here's what we know about jumpers:
* Appearance: It's described as a plain-looking garment with no apparent special features. It could be a cloak, robe, or even a simple shirt.
* Functionality: It allows the wearer to instantaneously teleport to another location, even if it's a considerable distance away. This is a highly advanced form of magic, requiring significant skill and understanding.
* Limitations: It's not clear whether there are limitations to the jumper's range or if there are any specific places it cannot teleport to.
* Known Users: Only a select few individuals are known to have used jumpers, including Dobby the house-elf, who used one to travel between locations while helping Harry.
It's important to note that jumpers are not commonly used in the wizarding world. They're considered very rare and powerful objects, and the ability to use them effectively is a sign of advanced magic skills.