Direct thread mount will attach the following suppressors directly to a threaded, fixed rile barrel: Omega 9 K / Omega 45 K, Octane 9/Octane 45/45 K, Harvester 300. This thread mount is not for use on pistols with unlocking or moving barrels. Product Specifications Category: Suppressor Accessories Series: Direct Thread Mount Model: Alpha Material: Stainless Steel Compatible With: SilencerCo Harvester 300 Thread Pattern: 1 / 2"x28