This is the main Spazer add-on for Grendizer.  Koji Kabuto is the pilot of the Double Spazer.  The Double Spazer helps Grendizer in air battles.  With this Spazer, Grendizer does not need to lock in and out of its own Spazer and risk being attacked in that process.  Now Grendizer can land and fly without any delays with the Double Spazer on its back.  The Double Spazer connected to Grendizer the most often out of all of the other Spazers.

The Marine Spazer is the second most vital Spazer for Grendizer.  This one allows Grendizer to move swiftly underwater and fight with more power.  Initially, Grendizer's power falls down by one half when the super robot is under the water.  Hikaru Makiba pilots the Marine Spazer, and with this weapon, Duke Freed does not have to worry about fighting Vegans beasts underwater.

Duke Freed's sister Maria Freed is the pilot of this weapon.  The Drill Spazer helps Grendizer dig underground and move very fast.  This weapon was the least used as a Grendizer add-on.