Cups may or may not include underwires for shaping. Lace cups are often lined with sheer tricot to add stability and reduce scratchiness. You can even add padding to the cups to make a push-up bra like the one below. Nonstretchy straps usually have some elastic at the back for ease of movement. Bras close in either the front or back with hooks, and back closures usually have two or three size adjustments.
Many sports bras pull on, with no closures at all.
To determine what size to start with, see Good fit . The underwire shapes and holds the cup to a fixed diameter, which can benefit even a small-busted woman. Complaints about underwires are due mainly to poorly fitting bras, which can cause pinching and poking wires. When making bras, you have the freedom to choose bright colors, jacquards, polka dots, or plaids, if you like.