This is a variation to the vanilla profit rate swap, which gives either the client or the bank the right to extend the swap at the maturity of the trade. If the client has the right to extend the swap, the fixed rate that they pay is slightly higher than the vanilla swap rate. If the bank has the right to extend the swap, the fixed rate that the client pays is slightly lower than the vanilla swap rate.
The arrangement is based on a Shari’ah compliant unilateral promise (waad) mechanism.