I just had to check. It is the Wilton 1 hp. I am not sure if I would like the 4". It all depends on what you want to do with it. The 2" is nice for fine tuning brackets and cleaning tubing. I kinda like how small it is. It makes it easy to maneuverer a tight radius when grinding a bracket.
I would say it is plenty of HP. Once it gets going, its hard to bog it down (unlike the HF woodworking one I purchased before this)
It kinda ***** for us metal guys. They only real option is this or a $800 + dedicated belt sander. No real in between. If there is, I couldn't find it! (it took me over 2 years to finally decide to purchase this.)
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