You haven’t experienced a true upper body workout until you add Jammer Arms to your Force USA G9®️ or G12®️ All-In-One Trainer. These legendary attachments work to isolate your arms, chest, shoulders and back so you not only keep perfect form through every rep but also reduce the risk of injury. If you’re looking to build explosive power and hit those strength goals, then this attachment is a must have for owners of the G9®️ or G12®️!