Balance accessories are optional supplies and replacement parts used with scales and balances. Balance accessories include draft shields, covers for wet and dry applications, computer interface cables, hooks and hangers, scoops, and sample pans. A draft shield is a cover, sometimes with doors, that is used with scales and analytical balances to improve accuracy by preventing airborne particles and airflow from affecting measurements. Covers help protect instruments from wear, airborne particles, and spills. Hooks and hangers are used for test tubes and specific gravity determination. Scoops are often used for loose samples including jewelry, food, and screws, and usually have a spout for pouring samples into packaging.