Salonpas Lidocaine 4% desensitizes aggravated nerves for powerful pain relief. The gel-patch technology delivers maximum OTC strength numbing relief directly to the back, neck, shoulders, and knees & elbows. Apply for up to eight hours of targeted comfort with this unscented, easy-to-use patch. It utilizes a hydro-gel based technology for long-lasting relief where it hurts the most.