Ingersoll Rand Sk4c3f 12Inch 3Pc Impact Socket Set. Ingersoll rand sk4c3f 1/2-inch 3-pc impact socket set. Click here for more images.Air tool accessories ingersoll rand sk4c3f 12inch 3pc impact socket set ingersoll-rand 3pc 1/2'' drive lug nut impact socket set. Includes socket sizes sae & metric flip socket & 3 ext. We are one of the nation's fastest growing retailers of tools and supplies, and we strive to be your number #1 source. We have a combined 26 years experience in the industrial tools industry.