These office chair arm pad replacement pads are of high quality material. The smaller than average size means they are less likely to strike your desk when in use. The mounting holes are spaced 4" apart from center to center. The density of the material fall in the mid to firm feel. Listing is for 1 case of 20 pcs. 80 screws included with each purchase. Your satisfaction is guaranteed or your money back. If for any reason you are not satisfied with your purchase, just return within 30 days for a refund of your purchase price (shipping charges not refundable). Volume discount available. Email me for details.