Beside $HRAA low float, I think $PGLO also has low float too, though its OS is 155M (higher than $HRAA of 55M).
If you look at the chart for $PGLO, in the last year trading, most of the daily volumes are 750k shares or lower. There were only 2 days which had volumes of around 1.25M and another was 1.50M or so.
tk