Poling relaxor-PbTiO(3) single crystals along pseudocubic [011] results in a macroscopic symmetry of mm2, enabling a large face shear d(36) in Zt±45° cut crystals. In order to allow the determination of electrical properties by the resonance method, square samples are required. Using Pb(In(0.5)Nb(0.5))O(3)-Pb(Mg(1∕3)Nb(2∕3))O(3)-PbTiO(3) crystals, piezoelectric d(36) coefficients were determined to be in the range of 2000-2500 pC∕N, with electromechanical coupling factor k(36)∼0.80-0.83. Mechanical quality factor Q∼180 and ultralow frequency constant of ∼500 Hz m were obtained. Together with the wide temperature usage range (up to ∼110 °C) and high ac driving field stability (∼5 kV∕cm), such face shear crystals have a promising potential for ultralow-frequency-transducer applications.