Also molded intotheexteriorofthe sump is an air intake hole, a threaded hole for the optional sump probe, and threaded holes forNPTfittingstoattach water effluent pipe. geotechenv.com geotechenv.com 另外在底盘外壳上带有进气管, 用于其他底盘探头的螺纹孔,以及适合NPT规格的接头的进水管使用的螺纹孔。