Silencer orders are fulfilled by one of our trusted partners, who will contact you to guide you through every step of the process. Please note that order cancellations may be subject to a fee. For full details on returns, warranties, and order policies, visit our Silencer T's & C's and FAQ pages Otter Creek Labs Polonium-K 5.56mm NATO 1.375 x 24 Suppressor with 1/2 x 28 Direct Thread Adapter - Black Cerakote - The Polonium was designed from the ground up to be a quiet, duty-rated, hard-use 5.56mm NATO suppressor that thrives under abuse. Available in both Standard and K configurations, it delivers one of the best size-to-weight-to-sound performance ratios on the market - period. If you want a suppressor you can run hard without worrying about babying it, the Polonium series is your answer. No gimmicks. No inflated or cherry-picked dB numbers. No marketing smoke and mirrors. The performance, durability, and real-world track record of the Polonium and Polonium-K speak for themselves. The precision 6mm bore isn't just optimized for 5.56 - it's fully compatible with 6mm / .243 cartridges, giving you greater versatility without sacrificing performance. An integrated internal and external flash hider system provides exceptional flash reduction - especially critical when running night vision or shooting in low-light conditions. When visibility matters most, the Polonium keeps your signature to a minimum. Its distinctive appearance isn't cosmetic - it's functional. Strategic external material reduction removes unnecessary mass while preserving structural integrity. The result? A suppressor that's lighter, just as strong, and features up to 10% more surface area (depending on length) to dissipate heat faster and cool down quicker between strings of fire. Run it hard. Let it cool faster. Get back to work. Both the Polonium and Polonium-K feature industry-standard 1.375 x 24 Rear Threads , giving you the freedom to choose the mounting system that fits your setup. No proprietary lock-ins. No limitations. Just compatibility and flexibility. If you want a suppressor that delivers elite performance without inflated hype - and can handle real-world abuse - the Polonium series is built for you. 1/2 x 28 Direct Thread Adapter ; 1.375 x 24 Suppressor Thread Pitch; After you place your order, you will be contacted by one of our fulfillment partnerswith additional info about next steps. A $10 Paperwork Processing fee will be charged for each suppressor. Purchases, cancellations, returns, and warranty claims for silencers/suppressors are subject to our Silencer Terms and Conditions . All silencer sales are final. Once a silencer is transferred to you, it cannot be returned. See our Silencer Terms and Conditions for warranty details. Please review our frequently asked questions (FAQs) and answers about silencers. Click here to review.