Wheel lug nuts often swell due to rust or over-torquing, making standard sockets useless. A flip socket solves this problem. It has two sizes, like 19mm and 19.5mm, on opposite ends of a single socket tube. You flip the socket to use the slightly larger half on swollen lugs. A square drive hole is located in the middle of the tube, allowing a short extension to drive either side. These sockets are impact-rated for use with pneumatic guns.
Mechanic Glossary
Flip Socket
A dual-ended impact socket featuring a different size hex opening on each side, designed to be used with a short impact extension.
Frequently Asked Questions
Many modern cars use steel lug nuts with thin chrome caps. Moisture gets trapped between the cap and the nut, causing rust that expands the outer hex size.
The most common sizes are 19mm/19.5mm and 21mm/21.5mm, which cover the majority of passenger cars and light trucks.
You just need a standard 1/2-inch drive impact extension. The socket fits onto the extension shaft rather than clicking directly into a ratchet head.