Product review (4 stars): Essential Tool for GE Washing Machines
I don't "like" this tool.  It is an accessory tool that is required to disassemble a GE washing machine tub assembly.  What I do like is that I got the part here on Amazon for $15 when it's almost four times as expensive anywhere else.  Shipping from non-Amazon 3rd party was very quick.  So this got one more star just for the customer experience.

Not only is this a proprietary tool, but it's not of high quality material and is made of a fairly soft metal.  When using the tool you need to really hit this spanner wrench hard to loosen the reverse-threaded nut located under the plastic washing machine agitator.  This tool is now all dented up with sharp metal edges from using it one time!

This tool saved me a $100+ call to an appliance technician, but I wish the tub didn't need this tool at all.  My shortest wrenches and pipe wrenches would not fit inside the tub or get a good grip to loosen the seriously tight nut.  There are a few CNC machined knockoffs on the Internet.  At the low price I paid I got the OEM tool.