The M4E1 PRO lower receiver is the next evolution of the M4E1 lineup. Machined from a solid 7075-T6 forging- this lower receiver is fully ambidextrous and seamlessly incorporates mirrored controls into the construction of the lower allowing for a reliable and intuitive user experience. - All proprietary componentry of this lower receiver comes preinstalled and is compatible with mil spec parts and components giving the builder the freedom to configure as they see fit. - Includes: - M4E1 Stripped Lower Receiver - Anodized Black - Bolt Catch Assembly - Magazine Release Assembly