Penis head pumps or penis tip pumps are a special breed of penis sen pump. This is a much smaller but equally as powerful penis pump. The actual cylinder (usually made of Acrylic, Plastic, or Glass) is typically less than half the length of a standard penis pump. The reason for this is that the pump should cover the entire tip of the penis and a little bit of the penis shaft. This will help create a nice strong seal which will help while pumping your penis tip. When you pump just your penis tip you drastically increase the blood flow to the most sensitive part of the penis, the head. Penis head pumps have been known to increase pleasure and sensitivity to the entire penis by at least 30%. This increase in sensitivity will cause stronger and more powerful orgasms. When using a cock ring around the shaft of the penis during pumping, you will see longer lasting results from the penis head pump.
More information on Penis Pumps from the MAYO Clinic.