This is an excellent no-clean tacky soldering and rework flux. Tacky paste consistency burns slower than liquid flux, and also holds BGA surface mount components in place for soldering. The ASM formula is Amtech™'s newest take on 559 with a little more rosin and different solvent than the V2 formula, giving it a higher boiling point that improves its use with solder paste as well.
This is the 10cc syringe that we use for iPhone microsoldering. It lasts us about 4-6 months with daily use.