GMS Gregory Mini Spacer Guardrail and Thrie Beam System is NCHRP 350 TL-3 and MASH approved and provides predictable and consistent release from a strong post every time. In addition to many safety advantages, the GMS (Gregory Mini Spacer) system eliminates the need for offset blocks and can be used with 12 ft 6 in., 6 ft 3 in. or 3 ft 1-1/2 in. post spacing at mounting heights of 27-5/8 in. to 31in. The system can be attached to transitions and end treatments of the same height. Uses all standard guardrail components.