This is for a outboard marine engine for the lower unit. I went to the D&R sports place and this was the only "marine gear lube" they had. It says it's safe for all outboard marine engine lower units without electric shift.

So I bought it but my manual which I learned after the fact says it needs SAE 90 hypoid oil. I don't what the heck that is and can't seem to find it anywhere? Any ideas? Is this 80W-90 oil safe to use for this purpose?