The Manual Extension Tube Set for Pentax K Cameras from Dot Line is an easy way to get extreme close-up photographs using your Pentax K camera and lens. Just attach your lens to the tube, attach the tube to the camera and move in close until your subject is in focus. All functions are in manual mode using these extension tubes. A set of three tubes is included: 12mm, 20mm, and 36mm. They can be used individually or together.