L203 flux works execellent on soldering dissimilar of aluminium alloy and copper alloy (1) Widest operating ranges using varied tin solders(40/60, 60/40, 50/50, 95/5 and lead-free solders). (2) Make solder flow quickly and evenly. (3) Pre-cleaning is not necessary under most conditions. (4) Competitive Pricing (5) Easily remove residue with water