IP (International Protection) ratings can be a little bewildering so here is a guide to help you choose between similar products with different ratings. IP ratings rate the protection against accidental touch, dust (1st digit) and water (second digit) in electrical enclosures.
Common ratings used on this website are IP44 and IP65, IP67
IP44 means dust resistant with gaps of under 1mm and splashes of water would not be harmful to the equipment.
IP65 means no ingress of dust and a 6.3mm water jet would have no harmful effect
IP67 means no dust and a 12.5mm water jet would not cause any problem.
If you are matching existing equipment to a new lead or adapter check the ratings of your existing connectors - if they are IP44 then IP44 will match what you have and IP67 would be better. If you have for example an IP67 lead then it would be best to match this up to an IP67 inlet. You can often tell the IP67 connectors by the locking ring which locks the connectors together, absent on IP44.