Some wheel nuts are manufactured with a permanently fitted chromium plated cap. These start off from the factory as a whole size, but over time due to the combination of corrosion and impact tool use, the wheel nuts can swell by up to 0.5mm. This double ended impact socket has one end machined to 27mm and the other to 27.5mm to overcome this issue. 1/2″D with 27mm & 27.5mm single Hex. Designed to use with 1/2″ short extension. Damaged wheel (lug) nut removal sockets. Overall length: 63.5mm. Ideal for use on 27mm chrome covered nuts that have swollen. Impact quality. Manufactured from chrome molybdenum.