From the product description, check product page for current description, price and availability:

• 【Food Grade 304 SS Material】 The Whole 2 micron inline diffusion stone(1/4 barb) is made of high quality 304 Stainless Steel,which let our 2 micron inline aeration stone is anti-corrosion & high temperature resistant & Durable
• 【Connected With Fittings】 1/2″ MPT diffusion stone can be installed into the 1/2″ FPT fitting or 1/4″ diameter for gas line to oxygen your wort & carbonating your beer. The diffusion stone can connect with kettle&pump&wort chiller by hose
• 【Lower Fermentation Times & Not Easily Get Clogged】 The 2 micron inline carbonation stone have millions of tiny pores ,so that this diffusion stone will quickly oxygenate wort & carbonate beer/soda prior to fermentation
• 【Detail Attention 】After carbonation, you can shake the beer keg.If do that, you beer can reach the best mouth-feel.Don’t touch the body of diffusion stone by your hands. The oils on your fingers can clog the small pores in the stone
• 【Boiled to Sanitize & Clean】 The 2 micron inline diffusion stone needs to be boiled in water to sanitize & unclog the pores.If the pores in aeration stone get blocked from handling give a 15 seconds dip in hydrochloric acid before rinsing with water