ReadyLIFT/Gorilla 6mm wheel spacer - 139.7 (6x5.5) GM 1500 bolt pattern.?These 6mm wheel spacers are designed to help new GM 1500 truck owners install aftermarket wheels that will not clear the new brake caliper boss. Ideal for those who don't want to have to go up to a 1'' or wider spacer just to clear the brake calipers.Safely provides 6mm of wheel offset without having to modify the wheel studs.?Can also be used to help to correct larger, wider tire to control arm contact on some applications.?Uses GM 1500 78.1 mm bore size.?Can be used on many vehicles that have a 139.7 bolt pattern, but check your hub bore size before purchasing.Sold as a pair.?