3. thickness of material: material thickness is often seen as good product, with a long, bad product is thin, cheap, used for any length of time is broken. Similarly locking too, good product materials thick, strong force, use it many times, and long service life. Poor products of thin force weak, which will be described easily damaged, use fewer and shorter.
4. start from the product assembly technology: products, good and bad, with long and short, Assembly technology has a great relationship with Assembly accessories. A good product together, all details of activities is quite flexible, rivets and springs are made out according to the dimensions of the product standard. Poor product assembled too tight or too loose, the gap is too big from side to side, rivets and springs is also non-standard, which will bring down the latch and the quality of life.