For those cock and ball pumpers, these giant cylinders are specially recommended for experienced pumpers who wish to build monstrous cock & balls or as a way to increase the size of your mushroom head. The design has a smaller opening at the base going into a larger cylinder with plenty of room for expansion. This allows the user a more comfortable size opening without sucking in more of the lower body. Please note that to make a cylinder 2 sizes needed please choose below. 30 Days Manufacturer Defect Warranty. PUMP SOLD SEPARATELY.