Drug-eluting stents are made from metal and coated with an antiproliferative drug. The drugs vary between the stents. In some stents, the drug is applied on a durable or absorbable polymer, whereas others are polymer free. Each drug-eluting stent has an instructions for use document that includes the indications for which the device can be used. The indications for use vary and may specify subpopulations or lesion types. They often specify the size of vessels the stent can be used for. Some stents can be purchased for use in specific cases because they are indicated for a particular subpopulation or lesion type, or because they have certain design features.