X type capacitor

How to identify x type capacitor? Are these better than polyester capacitors? I used polyester type but never used X type ones.

Thanks in advance.

Lavan: How to identify x type capacitor? Are these better than polyester capacitors? I used polyester type but never used X type ones.

Thanks in advance.

"X type" is a safety specification, not a capacitor type.

It means they can be used on mains voltages (110/220V) and will withstand surges, spikes, etc.

It means they don't catch fire, not that they will withstand all abuse unscathed... http://en.wikipedia.org/wiki/Filter_capacitor#Mains_filtering