Boat Trailer Keel Roller 5" Spool Keel Roller Bracket Assembly for 3" Tongue 32150G Stationary 5" Spool Keel Roller Bracket Assembly for 3" Tongue. Hot Dipped Galvanized Bracket has 3-1/2" Hole centers. Complete 1 piece roller and bracket assembly mounts on tongue or frame for added hull support. Does not include mounting hardware. (See Add-ons / Accessories)