Our Perfect Fit series of downrigger bases are designed to fit your downrigger perfectly. While you can use a universal base, the base plate mostly likely will hang out past the edge of your rigger making for a bit of an unsightly installation. The 4x4 Perfect Fit base has a top plate of 4”x 4” and is designed to fit Big Jon riggers perfectly. The Perfect Fit bases fit standard track systems from Berts, Traxstech, Cannon and others. Why not consider a Perfect Fit base for your downrigger installation, and save a few bucks too!