I have tried many,zoom+ was found to work the best.I used it for auctions and everything else.This so called replacement works when it wants to,and doesn't work well.I even tried using an old ff version to get zoom+back.ff "updated"my version so that didn't work for long.This is enough for me to give up on FF. The zoom feature is necessary for ALL the things I use the browser for.I have no reason to use the www w/o something to enlarge images.I'm old and have very poor eye site.I need to enlarge everything.I buy watches and parts.I had to quit repair work.Now I have to buy "blindly" greatly raising the odds against me.AS if it wasn't hard enough fighting thru the scammers on ebay.WORTHLESS EXTENSION