These are commercial grade inlays, not printed letters on vinyl tape. An inlay can not wear out. Unlike printed or painted stickers which wear off from the oil in a person's hand, the letter or symbol goes from the front to the back of the chip. Each chip is a thick piece of vinyl, not a piece of tape. Before installing, the consumer should inspect the back of the sticker. If the symbol is not visible from the back, it will not hold up under normal use. Fluorescent paint or ink will begin to dull in weeks. Others spray black paint or ink over a yellow background. The Fluorescent ingredient in these chips goes all the way to the back. LARGE FONT. 36 point inlays in Arial Bold Font instead of the normal 24 pt. font, creates symbols which are nearly 50% larger. The super stick adhesive that holds the vinyl chip will last a minimum of three years. The florescent Inlays are indelible and completely washable. They contrast with the black matte finish of the vinyl without causing glare which can irritate the eyes. A USB LED light, is also included. It can be plugged into any USB port on a computer, laptop, or notebook. It can be twisted or bent and will retain that shape (like a Gumby doll). It also can be used with a USB telephone charger or a USB compatible battery as a night light. The light is rated at 1.2 watts and will use any power source from 2 to 5 volts. The life of the light is guaranteed for 40,000 hours of use. Your satisfaction is guaranteed. If you should damage a sticker as a result of problems with the application, we offer a "Mulligan" policy. Send us a picture of the unusable sticker(s) and we will replace all of the stickers at no cost. The best tool to apply the stickers is a tweezers (included). This will allow you to line up the stickers, making the job look neater. Type: English US Alphabet. Perfect for people with corrected vision or for the elderly.