This is a mount for adding a toolhead sensor to the Dragon Burner extruder. 

It requires only: 

One small (12 mm wide) microswitch (endstop) 

One 4 mm metal ball (you can easily get one by taking apart a 608 bearing, which contains several of them) 

The design ensures excellent stability and reliable triggering. 

The sensor works very precisely and stays perfectly aligned even after long use.  

Simple to install  

Compact and sturdy design 

Fully compatible with Dragon Burner toolhead setups 

Printed part shown in the photos is made with standard PLA, but any rigid filament (PETG/ABS/ASA) will work fine.