The common light bulb interface standards for swimming pool lights are E27 and MR16, and PAR56 (Parabolic Aluminum Reflector 56) is a type of replacement light bulb. Only some pool lights have a common modular design that supports replacement light bulbs. It is best to confirm with the seller or manufacturer before buying.
LED pool lights with replacement bulbs are low maintenance and easy to replace.
Internationally renowned certifications related to underwater light bulbs
In order to unify standards and quality, some countries or international organizations have formulated relevant norms and certifications. Among the more famous are:
RoHS certification, CE marking, VDE certification, GS certification