Herman Miller Classic Aeron Chair Lumbar Pad - Smoke - Size C Plastic Made in USA Helps prevent back pain by supporting your lumbar region Pad adjusts vertically 4 1/2" while depth can be set at 3/4" or 1 1/4" by sliding the lumbar pad off and flipping it around Compatible with Classic Aeron Chairs (Sizes A, B, and C), Classic Aeron Stools, and Classic Aeron Side Chairs Size "A" - small, Size "B" - medium, Size "C" - large 12-year Herman Miller warranty