The KVP 3-Lug adapters are manufactured to replicate the popular HK pattern 3-Lug interface. Concentricity of ID and OD surfaces are paramount in any suppressor attachment. Machined in a high tolerance Swiss Lathe, these adapters have exceptionally tight ID to OD concentricity tolerances. To top it all off, the KVP 3-Lug adapters are Black Nitride QPQ finished to provide excellent wear properties for a long service life. 5/8x24 = 2.33 5/8x24 = 1.64oz 3-Lug Features: HK Style 3-Lug Adapter Swiss Lathe Produced Exceptional ID/OD Concentricity Black Nitride QPQ Finish