Standard 29rd magazine for WE Hi-Capa series. Also TM (Tokyo Marui) compatible. The 4.3 magazine is identical to the 5.1 mag except for a more rounded bumper plate on the bottom. They are interchangeable for a slightly different look if you wish :) Standard 31rd magazine for the WE Hi-Capa. Metal construction and fully TM compatible. Weight (Kg) 0.3500 Manufacturer WE Airsoft