xylene is a solvent (thinner). needed to clean brushes etc. no need,... throw away all that. you can roll it,... it will take two coats, sometimes a 3rd, but,... its an easy thing,... just like painting a wall but clear. there are many sealers available,... of all the differnet brands + types i've used to date for exterior, scofield (brand) gloss is it. 215-ish for a 5 gallon pail but worth it.
Often imitated,... never duplicated