1-Pair of WHITE Auto-Reset Child Safety Fall Prevention Devices WOCD 1761WHITE These WOCD's are sold in pair These Devices to be installes in place of existing vent stop openings. Be sure to check the drawing before purchasing to insure the product you buy will fit. If you are not sure please ask before buying 2-Devices are Required Per Window (1-left hand and 1-Right hand) per window Fit Slot Size: 1.875' X 0.285"