Tips for selecting a chair  A contoured backrest will give your back the comfort and support it needs. Pick a chair shaped to match the natural contour of your spine.      Global offers backrests that are height adjustable, providing your back with customized comfort and support.      Don't go too soft. For total comfort, seat and back foam must be dense enough to support your weight evenly and it should be sculpted to fit the human form.   Look for "waterfall" seat cushions that slope down at the front of the chair. This important ergonomic feature helps improve circulation to your lower legs.      Rest your arms. Armrests help keep your arms in a comfortable position, reducing shoulder, neck and back strain.       The pneumatic height adjustment on a Global chair lets you alter your seating position throughout the day with a smooth, easy, one-touch action.     Please remain seated. Make sure all adjustment controls can be reached from a seated position. Keep moving. Multi-tilt and operator mechanisms are important for data entry or computer work. They let you vary your position while maintaining maximum support.