What is the difference between tilt lock and tilt tension on an office chair?

Tilt tension (a knob under the seat) adjusts the resistance required to recline. Set it so reclining requires moderate pressure from your normal seated position — not too loose, not too tight. Tilt lock is a separate lever that locks the chair at a specific position. Use tilt lock for forward-leaning concentrated work; leave it unlocked for extended reading or screen work where periodic recline is beneficial. At OfficeFurniture2go.com, chair specs note tilt mechanism features — call 1-800-460-0858.