THIS IS A AUTHENTIC COLUMBIA HORN TANK, IT'S ALL CHROME, CAN FIT OTHER BIKES OR CUSTOM MADE BIKES, SEE THE ONE PHOTO SHOWS BOTH SIDES INSIDE THE TANK, IT'S 12-1/2 INCHES LONG OR SO, 1941 YEAR STYLE AND WILL FIT OTHER YEARS, THIS TANK WAS NOT MADE FOR MANY YEARS AND IS STILL LIKE NEW, IT'S IN NEVER USED CONDITION, CAN TAKE THE HORN BUTTON BATTERY TRAY AND I HAVE SOME IF NEEDED SEE IT IN MY EBAY STORE HORN UNIT, GREAT FOR RAT ROD BIKES.