This Mount was designed to be able to change the position of the Stack Top or Triple top to a Rearward or Forward position to better balance the units out evenly. You can choose 2 different Base Heights, 5 1/2" tall or 4 3/4" Tall. Having the ability to change positions can come in handy to help the closest unit not hit your shin whenever you can't move the mount forward due to the Bow design of your Boat.
Dual Stack Option:
Looking for a Triple Bow Mount - then go here: Bigfoot II - (Adjustable Stack / Triple Bow Mount)