It is a volatile options strategy, a variant on a ratio backspread (specifically a credit spread), which is the exact opposite of a call ratio backspread. It involves buying and selling put options, with number of the puts bought exceeds that of the puts sold. The position is always that of a net buyer, or long.
This strategy, like a typical backspread, makes profit when the underlying asset moves sideways, upward or downward. When the underlying is inactive or at a standstill, losses result. However, the put ratio backspread has, unlike other credit spreads, uncapped profit potential when the underlying’s performance deteriorates, and capped profit potential when it fares well (upside).
