What does 4D mean for armrests on an ergonomic chair?

4D armrest specification at OfficeFurniture2go.com is recommended for users switching between keyboard work, writing, and pointing device use — the pivot dimension fully addresses all positions. For standard keyboard/mouse users, 3D is sufficient. For occupational health applications with documented shoulder or neck positioning concerns, 4D is the clinical specification. Call 1-800-460-0858.