Unity Tactical Sordin Arc Rail Adapter Kit - BTH Black. Rather than reinventing the wheel the SARA calls on the spring tension generated by the Unity MARK rail adapters (sold separately) to achieve proper seal around the users ears and seamlessly integrate into the user's head borne system. Lightweight streamlined and designed with the simplicity and strength demanded by the end user the SARA eliminates the headaches and discomfort associated with wearing over the ear head-band Ear Protection inside the helmet. Specifications for Unity Tactical Sordin Arc Rail Adapter Kit: Manufacturer: Unity Tactical Additional Features: BTH Condition: New Package Contents: Unity Tactical Sordin Arc Rail Adapter Kit Unity Tactical HLM-SABB: Sordin Arc Rail Adapter Kit - BTH Black