"MagniClips™ magnifiers are effective for people who need to focus at an intermediate distance, such as a computer screen, or to do crafting or needlework. Even non-glasses wearers can wear them over their sunglasses when working or reading outside. MagniClips™ magnifiers come in +2.00, +3.00 and +4.00n magnifications. If you wear bifocals, choose +2.00 for an ntermediate focal distance & +3.00 for close-up bead work. Mono-vision wearers choose +2.00 or +3.00 for intermediate focal distance and +4.00 for close up bead work."