Balboa Water Group 30408 Pressure Switch 0.12 in. NPT 3A This Single Pull Single Throw &#40;SPST&#41; Pressure Switch for Spa Heaters is a 3 Amp Switch for a 1&#47;8 in. hole With a 3&#47;8 in. stainless steel thread. 2.0 PSI. Package Quantity: 1 Excellent Quality.