These are the best rings out there its what i use i didnt even need to use any sealant being i have cincrete slab didnt even need the spacer i just dropped gasket into the pipe set the toilet ontop & years later have no leaks, i will never go back to wax rings again its a conplete waste of money & a mess to clean thrm up when they start leaking which wax rings go out in a very short time, rubber fluid master rings will last many years with no worries.