Fertilizer Caddy fertilizer injector, 1 gallon capacity, 1" FPT inlet/outlet ASAE award-winning Fertilizer Caddy fertilizer injector 1 gallon capacity with 1" FPT inlet/outlet (female pipe threads) Proportioning fertilizer injector - injection rate is constant A minimum flow rate of 1 GPM and 10 PSI is required to function Perfect for drip and conventional sprinkler irrigation systems