The CBRN Hardened Uplink Module or CBRN/HUL, is an external attachment for ODST and HAZOP helmets.
The CBRN/HUL is available as a helmet accessory in Halo: Reach. The device for the ODST Helmet costs 1000 cR while the one for the HAZOP variant is priced at 2000 cR.[1]