The three tools you need to remove and instal a cassett are a cassett lock ring tool, a chain whip tool and a crescent wrench, the bigger the better. I would advise you to get some detailed instruction from books or otherwise on the removal of cassetts, because they are usually put on very tight and are of such a nature as to be easily damaged if you have to experiment in which direction to turn things. Good luck. I think you were bragging when you said that you had replaced others before. My experience is that the cassett lock ring tool is standard. This is certainly different than the old free wheel cogs. Every free wheel I encountered seemed to require a different tool.