Just bolt these onto your bulkheads using the included hardware. Each block has internal brass threads with Ruthex heat set inserts (yes, there is a difference) , brass washers, thumb nuts, bolt-insulating sleeves (to mount on aluminum or carbon) and stainless steel bolts. Just attach your wires from your altimeter to the bolts on the bottom side of your bulkhead and your e-match using the thumb nuts, and you are ready to go.
Provided are insulationg sleeves if you run metal/alumimum bulk heads.
There are two sizes available, large and small. Both use the same nuts and design, the larger one is easier dexterity, and the smaller one can save you some space.
There is no price differnece between the two as the true cost is the labor to install the heat set insert and hardware.
