Cold laser units come in various sizes and shapes. Often the units used are handheld and similar to the size of an average flashlight. A major advantage of cold laser therapy units is the ability to penetrate deep into tissues and joints while retaining the capability to also help conditions closer to the skin surface. People utilizing cold laser therapy as a non-invasive form of treatment report feeling little or no sensation during the treatment process. Regardless of how deep the light waves penetrate, the energy is eventually absorbed by the damaged cell providing it with the boost to begin working.