In one aspect, ultrasound transducers are described herein comprising monolithic caps having low acoustic impedance. Such transducers can be safer to use and/or simpler to manufacture. A transducer described herein, in some embodiments, a casing, a transducer element assembly disposed in the casing, an impedance matching layer assembly positioned over the transducer element assembly, and a monolithic thermoplastic cup enclosing the inner impedance matching layer assembly, the monolithic thermoplastic cup comprising side walls extending over side walls of the casing and an impedance matching bottom wall having an acoustic impedance of 1.5 MRayls to 4.0 MRayls.
