However, the quality of the SPR formula was determined by the suitable particle and detergent components and their appropriate concentrations in the suspension. For example, molybdenum disulfide and tergitol NP-7 were used as the particle and the detergent in SPR I, II and III. SPR II and SPR III were effective solutions, with proportions of particle to detergent of 13.1 and 13, respectively, whereas that of SPR I was 12.5. The important factors that affect the quality of SPR are the type of particle, detergent and their proportion.