Product review (5 stars): There is a great YouTube video on it
Perfectly fixed my washer leak from a 10 year old, worn out seal.  It took about 1 hour to replace, and most of that was taking apart the washer. There is a great YouTube video on it.  For the retainer rings, you don't need a special tool, if you're reasonably strong.  You can just use a couple of needle nose pliers.