Equipment usually used in water exercise programs is designed for variety, intensity, and program necessity. This guide discusses aquatic equipment under the following headings: (1) equipment design; (2) equipment principles; (3) precautions and contraindications; (4) population contraindications; and (5) choosing equipment. Equipment is used initially to add variety to the aquatic exercise program and later to increase intensity of the training program or for aerobic exercise. Equipment is based on one or more of three basic principles: buoyancy, weight, or resistance. Regardless of type of equipment, certain precautionary guidelines are to be followed: progressive overload; begin slowly; attain muscle balance; keep joints slightly flexed; keep the equipment in the water; stretch muscles at the end of the session; move toward and away from the body center; always place, not fling, the piece of equipment; use equipment only after warming up; use full range of motion; know where the equipment is going; and use proper alignment. Those using equipment should not have medical contraindications. Considerations on choosing equipment have to do with its purpose, participants, and such items as cost, ease of storage, resistance to mildew. (AMH)