Response of the brand
Thank you for taking the time to post a review of you track pump. I'd like to confirm that this pump head can accept both Schrader and Presta valves. To convert to Presta, you need to unscrew the top cap on the valve, invert the two internal spacers, re-insert them in the same order and screw the top cap back on and voila. To make it clearer, please go to the website, locate the pump and the 5th image will demonstrate more clearly how to switch the spacers. Please give this a go and if no joy, don't hesitate to get back in touch.
Regards,
Peter, Cycling Manager, DECATHLON