CA metal upper and lower. This set is Marui compatible, you can drop a V2 in and use a M4 hop up unit. However, it is designed to be used with CA/Apex blow back gearboxes, so the charging handle normally connects to the mock bolt on the gearbox. If you don't have one, there is nothing for the handle to connect to unless you modify something. Comes with parts shown only. Thanks for looking, message me with any questions. If I don't reply, please feel free to send another message. Sometimes they don't go through or I miss them. Accepted payment methods are HopUp payments, PayPal, and Cash App. PayPal is preferred. Tap my name to see my other posts!