These designer bag knock-offs look similar but are much lower in quality.

knock-offs 是复合名词，由动词短语 knock off（意为"快速制作、仿制"）加连字符和复数后缀-s构成。在商业语境中，knock-off 特指"仿制品"，尤其指模仿名牌设计但质量较差的商品。