Disclaimer:
I received this set for evaluation from Banggood, and did not have to pay for it. However I have tried to be impartial in my judgement of these bits.

Features:
The set of 12 tap drills, 6 each in Metric and SAE sizes, comes with a bit holder which enables quick changes on your drill. The bit holder has a spring loaded catch which holds the drill bit once it is inserted. To release the bit you have to pull back on the ring. I found this to be a very practical feature. The Metric bits in my set seem to have a yellow coating on them, but the SAE bits do not come with any such coating. The set comes in a well made, sturdy plastic case, with good hinges and a sliding lock, all built to last. The bits and the case arrived undamaged, and without a hint of rust or dent damage. This was so even though a couple of the bits worked themselves loose from their cylindrical holders within the case.

Usage:
I have tried the bits out on Aluminium sheet, upto 4 mm thick, and also Aluminium rod, upto 25 mm in diameter, as well as Acrylic sheet. In all cases, the bits cut well, and the tapped threads were formed well too. With Aluminium I used WD-40 as a cutting lubricant, to increase the life of the bits and to control "sticking". I have not yet experimented with mild steel, but the bits look good enough to tackle at least thin sheet upto say 2 mm in thickness. I also used it on acrylic sheet and there too the results were decent. I note that other reviewers speak of using it on 3-d printed parts (PLA/PETG/ABS plastic), and I would imagine that to be an excellent application for this set.

Overall:
Overall, I think these are good value for money and a recommended addition to any workshop.

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