Per an email from Dicor, the 502 is the same but is intended for machine dispensing. Manufacturers use it I guess.
They said I could use either one for my satellite dish.
The email reply:
"The 501LSW was developed to be used at the consumer level. The 502LSW was developed to be used in a pumping system at the manufacturing level. Very little difference with the exception of case quantity.
Any or all of Dicor’s lap sealants will work for your application depending on whether you need a self leveling or non-leveling lap sealant.
Clay WA5NMR - Ex Snowbird - 1 year, Ex Full timer for 11 years - 2004 Winnebago Sightseer 35N Workhorse chassis. Honda Accord toad.