Rugged Suppressors 3 Lug Adapter Obsidian Accessoies 13.5x1 LH Tpi Black. 5x1 LH tpi Black - The 3 Lug Adapter features the patented Go/No Go Gauge. The No Go/Go Gauge provides confirmation that your suppressor is properly attached for a surprise free shooting experience. The 3 Lug Adapter is compatible and used in conjunction with our 3 Lug Mount. This 3 Lug Adapter is made to 9mm HK spec. and is not compatible with 45ACP. Specifications for Rugged Suppressors OA004 3 Lug Adapter Obsidian Accessoies 13.5x1 LH Tpi Black: Manufacturer: Rugged Suppressors Finish: Black Rugged Suppressors OA004 3 Lug Adapter Obsidian Accessoies 13.5x1 LH Tpi Black