Wetsuits have one job--to keep surfers and divers warm. But even though they all have the same purpose, they're built in different ways. Wetsuits come thick or thin, stretchy or rigid, permeable or watertight. They can leave the arms and legs exposed, or they can cover the entire body. Suits vary in price; cheaper suits generally are best for warm-water use, while higher-priced suits will stand up better to cold water.
According to the Surfing Blog, wetsuits come in three basic styles: Spring suits, long john suits and full-body suits. Their names reflect their designs. Spring suits, also known as shorties, cover the core but not the arms and legs, and they're best in warmer weather. Long john suits cover the core and the legs, but they have short shirt sleeves. They resemble overalls, leading surfers to call them Farmer Johns and Farmer Janes. Full-body suits insulate the core and the limbs.
A wetsuit's thickness dictates its warmth. Thicker wetsuits are warmer, and warmth typically is measured in two numbers. The first indicates the suit's thickness around the body's core, and the second applies to the arms and legs. For example, a 3/2 wetsuit is 3mm thick at the core and 2 mm thick on the arms and legs. Other common thickness measurements are 4/3 and 5/3.
A suit's stitching also factors into its warmth. High-quality stitching locks cold water out, while cheaper stitching allows water inside and compromises the suit's insulation. According to Wetsuit Gear, warm-weather suits have flatlocked stitching, which is layered at the seam and resembles railroad tracks. Blind stitching combines glue and stitches at the seams and allows less water to seep inside. Reinforcing blind stitching with tape strengthens the seal and is recommended for use in extremely cold water.