Ska punk is a fusion music genre that combines ska and punk rock. Ska-core is a subgenre of ska punk, blending ska with hardcore punk. The characteristics of ska punk vary, due to the fusion of contrasting genres. The more punk-influenced style often features faster tempos, guitar distortion, onbeat punk-style interludes (usually the chorus), and nasal, gruff, or shouted vocals. The more ska-influenced style of ska punk features a more developed instrumentation and a cleaner vocal and musical sound.