> If you are buying a replacement part you would want to buy one with the same specs as the part you are replacing. But without the paper, you cannot know for

> If you are buying a replacement part you would want to buy one with the same specs as the part you are replacing. But without the paper, you cannot know for sure if the spec is the same (you can't see the difference between aviation grade screws and regular screws with naked eyes for instance). > Manufacturers will test their parts so that buyers can see if the part is usable for their needs. Manufacturers want to sell their parts, they don't want buyers to “see if the part is usable for their needs” (if the buyer doesn't buy, that's a missed sale). I mean have you never buy anything? Sellers want you to believe their product is good so you buy it and they make money, that's how it works. And customers being disappointed by false marketing promises is routine stuff, including in the B2B sector.