noun, noun-modifying (irregular), noun which may take the genitive case particle 'no'
assembly-style; knockdown; flatpack; prefabricated
Describes items sold in parts that the buyer assembles, such as furniture, shelves, or equipment. Often used with 家具 (furniture) or 棚 (shelf).
この本棚は組み立て式なので、自分で組み立てる必要があります。
This bookshelf is assembly-style, so you need to put it together yourself.
組み立て式の家具は引っ越しのときに便利だ。
Flatpack furniture is convenient when moving.
完成品 is a finished product, ready to use without assembly, while 組み立て式 requires the buyer to assemble it.
Compound of 組み立て (assembly) + 式 (style, type).