The Solder Paste is a high viscosity no-clean flux, it can be used for PCB, SMD, reworking, it can be used for soldering and reballing of computer and phone chips .
It is the mixture of high-quality alloyed powder and resinic pasty flux, it can avoid the pale yellow residue, so you are easy to clean the board.
AMTECH Flux Type RMA-223-UV BGA PCB Flux Paste SMT