There are three main technologies: Ultrasonic devices, Chemical/Scent repellents, and Physical barriers. Ultrasonic devices emit high-frequency sound waves (20kHz-65kHz) that are distressing to rodents but inaudible to humans; look for models with variable frequencies to prevent rats from adapting. Chemical repellents use essential oils (peppermint, camphor) or bitter agents (denatonium benzoate) to create an olfactory or gustatory deterrent. For B2B sourcing, ultrasonic electronic units are currently the highest-demand category due to their longevity and lack of mess.