Knipex 8801180 7-1/4-Inch Alligator Pliers
Self locking on pipes and nuts with no slipping on the work piece.  The optimized jaw shape will grip round, square and hex shape materials.  The box joint design is highly stable because of the double guide.  The guard on the handle prevents the fingers being pinched as the handles are squeezed together.  The 3 piece set will cover pipe capacities from 1-1/4" to 2".