Shakespeare Stainless Steel Boat Antenna MountShakespeare's Style 4187 is a stainless steel ratchet mount featuring a versatile four-way design that adapts easily to deck or side mounting on slanted or level surfaces. Its simple design makes installation simple. The quick action handle makes raising and lowering the antenna easy, and the ratchet makes it easy to return the antenna to its correct, upright position. Bolt Holes: 5/16" diameter, 3" x 1-1/2" on center; Standard 1" - 14 thread (male); Stainless steel;