K400S Diamond Heavy Duty Hatchback/Trunk Mount - Secure Lip Mount

In this review the K400S K-400S Diamond heavy duty trunk and hatchback mount is evaluated for installers who need a sturdy, no-drill solution for mobile antennas. The bottom line: this mount is for users who want a secure lip mount that protects the vehicle surface while clamping a larger antenna firmly in place. It stands out for durable construction and a four set-screw design that keeps antennas stable under driving conditions, and the review focuses on build, install, and compatibility with handheld and mobile radio setups.

Key Features

• Heavy duty trunk/hatchback mount: Built to clamp to a hatch or trunk lip so larger antennas stay solid even at highway speeds.
• No drilling required: The rubber mounting pad protects paint and sheet metal while avoiding permanent modifications to the vehicle.
• Four set-screws: Four screws clamp the mount tightly for a reliable hold that customers describe as particularly secure for bigger antennas.
• SMA connector option: An SMA connector allows direct connection to HT handheld radios without additional adapters, simplifying portable use.
• Includes RSA3474 adapter: The supplied adapter lets the mount be used with typical mobile radio PL259 connections for easy integration into vehicle installs.
• Two-axis adjustability: Simple angle adjustments let users position the antenna for clearance and best performance on uneven surfaces.

Who It's For

The K400S mount is best for amateur radio operators, CB and two-way radio users, and anyone mounting a larger antenna on a hatchback or trunk who wants a no-drill lip mount. It suits owners who value protection of the vehicle finish and need a mount that can clamp tightly to resist vibration and wind load.

It is less appropriate for users who need a permanent, welded bracket or those who require a recessed roof or magnet mount solution. Also, buyers seeking a budget-only option should be aware some find the mount pricier than basic mounts, though they note that the quality justifies the cost.

Pros & Cons

Pros

• Solid build quality that customers praise for holding antennas securely.
• Protective rubber pad avoids paint damage and makes installation reversible.
• Includes RSA3474 adapter and SMA option for flexibility with HT and mobile radios.
• Two-axis adjustment and four set-screws provide a dependable, adjustable clamp.

Cons

• Some buyers may consider the mount more expensive than minimal alternatives, though many say it is worth the price.
• The design is specific to trunk/hatchback lips and is not suitable for roof or magnet-only installations.

Specifications

Product name	K400S K-400S Diamond Heavy Duty Trunk Mount
Mount type	Heavy duty trunk lid / hatchback lip mount
Connector options	SMA for HT radios; includes RSA3474 adapter for PL259 mobile radios
Cable	13.5 ft of RG316
Mounting pad	Rubber pad to protect mounting surface
Adjustment	Two-axis adjustable with four set-screws
Installation	No holes or drilling required

Our Verdict

The K400S Diamond heavy duty hatchback/trunk mount is a practical choice for radio users who need a secure, vehicle-friendly lip mount. Its protective rubber pad, four set-screw clamp, and included RSA3474 adapter deliver reliable performance and compatibility with both handheld and mobile radios, making it a good value for those who prioritize build quality and a no-drill install.

Frequently Asked Questions

Can this mount be used without drilling?
Yes, the K400S is designed for no-drill installation with a rubber mounting pad that protects the vehicle surface.

Will it work with handheld radios?
Yes, the SMA connector option lets users connect handheld HT radios directly, and an RSA3474 adapter is included for PL259 mobile radio connections.

Is it secure for larger antennas?
Customers report the four set-screw clamp holds larger antennas well and provides a very secure mount under typical driving conditions.