A1 Handguard Each of the A1 handguard halves are lined with aluminum heat shields, to help protect you and the handguards themselves from the barrel heat. A1 Triangular Carbine Handguard (XM-177) Enhanced control and accuracy with the A1 Triangular Handguard (XM-177). Made from high-quality materials, this durable handguard provides a comfortable and secure grip for your firearm. Its unique triangular shape offers a unique look and improved handling. Upgrade your AR with the A1 Triangular Handguard. Each of the handguard halves are lined with aluminum heat shields, to help protect you and the handguard from the barrel heat. Material: Dupont Zytel 30% glass filled nylon. Mfg: Luth-Ar