From the manufacturer:
SPADA-S 13.5'' Freefloat Handguard
Machined from Extruded 6005A-T6 Aluminum and Type 3 Hardcoat Anodised, Class2 Deep Black.
Durable and Robust design with Ultra narrow diameter, 1.55'' OD.
Zero Protrusion over Upper Receiver allows the handguard to be mounted to any upper design regardless of shape or size.
Built in Anti Slip & Anti Rotation system, strengthens the handguard in the receiver end area and allows strong clamping onto the barrel nut. Handguard cannot be removed from the barrel nut without removing all three fixing bolts.
Bolts are Grade 8 Steel, Black Oxide Finish.
Comes complete with 2.5'' RES (Rail Extension System) & 1.5'' of Picatinny Rail.
Weight 10.0oz including Mounting Hardware.
Made in the USA.