RGZ-91 Re-GZ (RGZ-91 リ・ガズィ) is an attempt by the Earth Federation to create a mass-produced version of Z Gundam. Its name is literally "Refine Z Gundam". To try to cut costs, engineers thought to remove the expensive Wave Rider equipment with a similar but easier to produce Back Weapon System (BWS). It allows Re-GZ to transform into a Wave Rider like form and can be attached to Re-GZ like a back pack. Whilst transformed, it can fire from additional artillery not otherwise found in its two-legged form to defend itself.