Do you want to replace the upper and lower of your M4 for another model such as a Daniel Defence? Take a look at our assortment here!
Trident Mk2 Upper Receiver Assembly FG
Madbull Daniel Defense M4 Metal Body Ver 2 with Ultimate Hopup
Madbull Barret M4 Metal Body Ver 2 with Ultimate Hopup
G&G Delta Force Metal Body for G&G