Polypropylene cam-locks are fibreglass reinforced for extra strength. They are often used where weight is a concern, for example on portable forest fire fighting equipment. All sizes come complete with stainless arms. The black polypropylene parts are more economical and suitable for a wider range of chemicals. Female couplers are supplied with locking clips. Working pressures provided at 20°C. As temperatures rise, working pressures for these cam-locks drops dramatically. At 93°C, pressure ratings are reduced by 50% for polypropylene fittings. Please note, cam-locks should not be used with compressed air or other gases.