This Bigfoot mount was designed to support one graph (Many Hole Patterns) with the capabilities of upgrading to a Dual Stack mount by adding the Stacker Top. You can get the Single Riser or Stack top Here - TM Pedal - Bow Mount Straight Single Riser / Dual Stack
Note: The 5 1/2" Tall - Inside measurement between the Legs is 13 1/4" and over all width footprint is 18".
Note: Superwide 5 1/2" Tall - Inside measurement between the Legs is 16 1/4" and over all width footprint is 20 3/4"".
Note: The 4 3/4" Tall - Inside measurement between the Legs is 12 1/2" and over all width footprint is 15 1/2".