This Sensei 52mm Quick Clip Lens Hood is designed to mount quickly and easily onto your camera lens to prevent lens flare in your images. This two-part design allows you to leave the threaded ring on your lens and easily clip on the hood when needed, or easily reverse the hood when you find it unnecessary. This lens hood is for use with internal focusing lenses and non-rotating filters, and accepts center-pinch lens caps. To avoid any vignetting, the Quick Clip is best used with lenses above 20mm for 35mm format and with lenses above 15mm for APS-C format. In addition to keeping stray light out, it can help protect your lens and minimize accidental damage from everyday use.