Toro 640 Series Gear Driven Rotor Sprinkler Package COM (Check-O-Matic) 35 Years of Reliability Once the 640 Series sprinkler goes in the ground it stays there. With a stainless steel-encased nozzle assembly and gear drive design. Check Valve Standard Prevents low head drainage puddling and soil erosion Durable stainless steel engineering plastic and brass construction for reliable performance in the most demanding environments Normally Open Valve-In-Head Body Allows individual head control - the only commercial grade Toro rotor available with this feature.