The Manfrotto 116SCK3 Suction Cups with Retractable Spiked Feet fit upon the 190CXPRO4 tripod.  The suction cups increase the tripod's effective footprint by ~20x, yielding a significant increase in stability when needed upon certain surfaces.  Retract the rubber cup to reveal a steel tip which provides a firm footing on soft ground.

These tripod feet can be removed and replaced at will, even in the field.