Designed for AXOLOM STP packer and play, our rods are made of two different textures silicone, the front part is hard to fill the STP precisely. The base part is made of super soft silicone as our packers, fully filled the cups, and let you feel comfortable when play with it. Our rods are one-to-one compatible with our STP designs, please select the correct rod for your STP by the item name! Or it would not work with your STP. (If you have a Zeus STP, please select this page item.) Lube is needed to insert the rod easily. And please press and hold on the HARD Part (NOT on the soft pad) when you pull out the rod from STP, to avoid tearing.