The HUXWRX Direct Thread Adapter M13.5X1 LH is designed for compatibility with RAD 9 and RAD 45 suppressors, ensuring a secure fit for your fixed-barrel system. Constructed from durable 17-4 stainless steel, this adapter is heat-treated and features a black nitride finish for enhanced wear and corrosion resistance. The wrench flats allow for easy and secure installation, making it an essential accessory for those looking to optimize their suppressor setup. Please note that this adapter is not intended for use on unlocking or reciprocating barrels.