Prier 1/2 In. SWT X 1/2 In. IPS Anti-Siphon Frost Free Wall Hydrant Self-draining. Mansfield anti-siphon frostproof sillcocks assure protection against freezing and undesirable back-siphoning. Because they're frostproof, they can stop outside hydrants from freezing and bursting the pipes. Plus, the anti-siphon feature protects against water siphoning back to contaminate the potable water system. Also, unlike anti-siphon attachments, which must be manually drained to prevent freezing, the integral anti-siphon design is self-draining. 1/2 sweat inside, 1/2 IPS outside. Size 1/2 In. SWT x 1/2 In. IPS, Length 12 In., Finish Nickel Plated, Material Brass, Pkg Qty 1 WARNING This product can expose you to Lead and Lead Compounds which are known to the State of California to cause cancer. For more information go to www.P65Warnings.ca.gov.