headdict
100+ Head-Fier
depending on the tips, I find that most shure and westone products have a very ok isolation. but I don't know if there are any products that can give the isolation of the er4+triflange in non custom.
SE425 with stock tri-flange works very well for me, isolation-wise. Both isolation and comfort are ety grade. However, I use them with star tips, because isolation is still ok, but comfort is much better.