Humminbird (Blue)

Round Base: 3.75" Round (same hole pattern as 2.25" ball RAM)
Bullet Base: 3.75" x 2.1875" Rectangle (2.5" x 1.5" 4-hole pattern)

Installation Hardware Kits are offered to fit MOST applications. 

All 18-8 Stainless Steel

Includes:

(4) 1/4-20 x 2.5" Flat Head Bolts w/ 1.25" Fender Washers for the bottom side. (For the Base)

(4) 1/4-20 x 7/8" and (4) 10/24 x 7/8" Button Head Bolts (depending on the application) for the gimbal. 

-All bolts come with flat washers and nylon insert lock nuts