Perforated or Spiral Cooling Towers The Perforated and Spiral Cooling Towers protect pressure instruments during high temperature applications. Both the spiral and perforated styles are made with 316L stainless steel and are available with various process connections in NPT or BSPT style. Both Cooling Towers are ideal for use with pressure gages, switches, and transmitters where the process media temperature exceeds the rating of the instrument. Specification Service: : Compatible liquids and gases. Wetted Parts: : 316L SS. Temperature Limits: : 428°F (220°C).