I've used several slip on chucks over the years, mainly the right angled "crack pipes" to inflate disc wheels. Rarely was it an 'easy' job to inflate tires, but it worked, so I put up with it. Recently, I've been using a thread-on presta chuck that has, on occasion, loosened my valve cores upon removal, causing slow leaks that I'd realize at some point on my ride (very frustrating). So, I decided to give the slip-on pump head another try and the Schrader threaded end of the Silca Presta Chuck was easy to adapt to my pump. Oh my, am I impressed! This is the easiest slip-on chuck that I've ever used. The Chuck seats onto the valve easily (smooth and threaded valves alike), stays on the valve without needing to be held, and slips off very easily too. It does what a pump head should do, better than any other that I've used. Thanks Silica!