This is ROHS compliant Lead Free soldering wire.
SAC0307 is cost effective replacement of SAC305 with reduced amount of Silver and tradeoff 8C higher melting temperature, which is not a problem with hand soldering.
Thickness 0.8 mm is very good for PCB with small-medium SMT components repair and retouch. It’s also good for normal PTH components soldering, but not as good for big PTH components as you have to feed lot of wire to solder the big PTH component leads.
Soldering iron temperature must be set between 245 and 375C.