When it comes to trims used in garments, certain materials need to be preshrunk to prevent any undesirable changes in size after washing. Let's evaluate the options:
(1) Buttons: Buttons typically do not need to be preshrunk as they are made from materials like plastic, wood, or metal, which do not shrink.
(2) Laces: Laces, especially those made of cotton or other natural fibers, may need preshrinking. These materials are prone to shrinkage when exposed to water or heat, so preshrinking ensures they do not shrink after being sewn onto a garment.
(3) Studs: Studs are usually made of metal or plastic, which do not shrink. Therefore, they do not require preshrinking.
(4) Hardware: Hardware (e.g., zippers, hooks, or eyelets) is typically made of metal or plastic and does not require preshrinking.
Thus, the correct answer is (2) Laces, as they may need preshrinking due to the potential for shrinkage, especially if they are made from natural fibers.
Laces, particularly those made from natural fibers, often shrink after washing. To prevent changes in fit or design, they are preshrunk before use. In contrast, trims like buttons and hardware are unaffected by washing.