Ratchet mount adapter, 4 inch long, with 1 inch x 14 female thread one end and 1 inch nipple other end. Made of acetal plastic. This eliminates any risk of dissimilar metal corrosion between your antenna and an aluminum or stainless steel mount. 

Morad Adapters:

• Made entirely in the USA.
• Precision machined and finished by hand with modern tooling.
• Individually quality tested before shipment.
• Dependable and rugged.
• Our products are trusted on military, law enforcement, commercial and leisure vessels around the world.