Power cord upgrade for Outlaw 7700 amp (rectangular plug shape)

Hi there. Having trouble finding a power cord upgrade for Outlaw 7700 amp. Ideally I'd pay less than $300 and have a decent return policy. This appears to require a less common connector--it's rectangular in shape. Rear panel pic can be viewed here:  https://outlawaudio.com/images/7700rearusa.jpg

Appreciate your suggestions--


 That is a C19 connection. You need a 20 amp power cord.  I would suggest buying used. Something like an old Shunyata Black Mamba would be a great power cord.