There's a difference! Polyester capacitor, also known as polyester capacitor symbol is CL, the capacitance is generally 40p--4μ, rated voltage 63-630V, the main features of small volume large capacity heat and humidity resistance but poor stability is generally used in the stability and loss requirements of low frequency circuit. Polypropylene capacitor is CBB capacitor, the capacitance is generally 1000p-- 10μ, rated voltage: 63-2000V Main features small size, good stability, can replace most of the polystyrene or mica capacitors, used for higher requirements of the circuit.