What's the difference between a HYPO Key and a Woodruff Key?

I need a split pin/tension/spiral pin 7/32 dia x 1.125 or 1.250 long. Have a source? Sears p/n 59294. NLA from Sears

How about key, Hypo 3/16 x 3/4 (from Sears site), Sears p/n 59240? Slot in shaft is about 0.200" wide and 0.600" L. The height of a replacement pin would be about 0.250". I guess it makes sense. Key is available from sears. It's part of a clutch assembly. A pulley must easily slide over key. Any idea how to size these beasts from shaft measurements?