UPDATE: I ordered the Kohler pump Kohler 1041645 Soap and Lotion Dispenser Pump Assembly for $1.43 from Amazon, and it is compatible to the Grohe pump. I would not recommend the Grohe pump anymore. The Kohler appears to be of the same quality as the ELKAY Grohe. Since Amazon stocks this pump, you need to order over $25 of stocked items to get this. As much as I like Grohe's products and own them extensively, the soap dispenser is a flop, and requires a lot of maintenance, until it fails. The pump is poorly designed. The soap dispenser itself has this problem that the nozzle and connecting brass tube is too narrow. This means that if you don't use your dispenser frequently, the soap inside the nozzle and tube dries up, and you then need to use a stiff wire such as a paper clip to open it. I have solved this problem by drilling a hole at the end of the nozzle and enlarging the brass tube itself by drilling. But the pump is a disaster. It fails after a while, especially if left unused. I traced the problem to rust, which permeates the ball bearing and the seat, and hence the ball valve fails to operate. It either fails altogether, or it works but gradually the soap is lost, and then the pump stops working. One source of the rust is the ball bearing itself, which is supposed to be stainless steel. Obviously it is a cheap imitation ball, and you can see rust marks etched into the ball, when it is supposed to be perfect. There are other sources of rust, which I have not been able to determine. The rust causes the ball not to seat perfectly, and hence the pump loses soap and prime. Sometimes the pump works with plain water, but refuses to work with soap. Taking apart the pump and cleaning it out, works about half the time. Other times the pump fails for no apparent reason. In some dispensers it is impossible to separate the pump from the head brass nozzle, and the connection is just too tight. Out of 10 dispensers that have failed on me, I have been able to resurrect about 5 of them. The others I have bought new pumps from Amazon. To resurrect a pump, you need to open it up. To open the pump, you must cut an incision where the top of the pump mates with the body of the pump. The incision should cut both flanges and go down about 3/8", and just deep enough to cut the body plastic (and flange), but not deeper. Then you can pull the top part off the body and open it. Do not damage the body or the plunger in this process. Clean the ball and spring and the plastic seat (gently). I would not recommend the Grohe soap dispensers if they are not used frequently. As for this replacement pump, all that I have ordered have worked. Question is when will they fail, in particular if they are not used everyday. Note: if the soap is too thick, the pump will get clogged and will not work. Soap will dry up after a while and if the soap in the bottle is heavy, then replace the soap. The pumps seem to work better with less viscous soap, so add water to your soap.