The NMOKHFCXTHK vehicle roof mount antenna installation hardware kit is a special application NMO mount for Motorola-style mobile antennas 0-1000 MHz in thick surfaces. This nickel, copper and zinc alloy permanent mount is for a 3/4 inch hole in mounting surfaces up to 1/2 an inch thick. The vehicle roof mount is also convertible to support high frequency applications 0-6000 MHz because of the removable center pin. The mobile antenna mount includes 17 feet of RG58A/U cable. Order connector separately. Thread size is 1 1/8 inch - 18.