Generalaire 990-37-75 Orifice & Strainer Assembly   (Part # 7009)

For low water pressure - 20-40 psi.  Fits whole house humidifier models:

• 1042 (1042-L, 1042-LH)
• 1040 (1040-L, 1040-LH)
• 1137
• 709 (709-L, 709-LH)
• 1099 (1099-L, 1099LH)