It is the gen4 iteration and comes with (3) magazines and the four back straps that typically come with Gen4 models.
Elite Tactical Systems Group, Elite Tactical Systems Group, Magazine, 10MM, 20 Rounds, Fits Glock 20/29/40, All Generations, Polymer, Clear
Each GLOCK magazine is constructed from a hardened steel insert encased in high tech polymer to protect the magazine and prevent deformation, even when dropped from a great height.
GLOCK, OEM Magazine, 10MM, 10 Rounds, For GLOCK 20, Cardboard Style Packaging, polymer, Black
Glock, OEM Recoil Spring Assembly, G20 & 21
OEM trigger housing for GLOCKs in 10MM or 45ACP
ETS magazines are made from advanced polymers that provide extreme impact resistance, so they won't crack or break when dropped.