The 125 S 200 typically refers to a bronze swing check valve with a WOG rating of 200 psi and a nominal size of 1/2 inch. Here's a breakdown of what that means:

Product Overview: 125 S 200 WOG Swing Check Valve

• Type: Swing check valve
• Material: Bronze (corrosion-resistant, suitable for potable water and non-corrosive fluids)
• Size: 1/2 inch (nominal pipe size)
• Pressure Rating:
  • WOG 200 = 200 psi for Water, Oil, and Gas
• Connection Type: Typically threaded (NPT)
• Function: Prevents backflow in piping systems by allowing flow in one direction only