I'd imagine the Poverty cranks have a 19mm axle, that or it's imperial 3/4" which is 19.05mm, is it sealed bearing? if it is you should be able to get the axle size from the bearing number. Most aftermarket sprockets are larger than 19mm and come with a top hat spacer to fill the gap, make sure it fits tight on the axle and in the sprocket ot it will come loose a lot.