mpo55Danfoss MP 55 Differential Pressure Switch is used in refrerating systems with R717 and also systems with HCFC and non-flammable HFC refrerants. MP 55 Pressure Switch has a fixedMP55 is In-Stock at Kemko Aerospace, a California based company dedicated solely to the supply of hh-technology chemicals such as: Coatings, Sealants, Resins, Adhesives,