Abstract: The pump includes a piston slidably mounted in a metering chamber, the piston including a support, a diaphragm made of a first material and forming a check valve that allows fluid to flow into the metering chamber, and a presser element for pressing the diaphragm against the support, the presser element including a skirt carrying seal enabling the piston to slide in leaktight manner in the metering chamber, the presser element being made of a second material different from the first material of the diaphragm, being fitted against the diaphragm, and having a diaphragm presser surface that holds the diaphragm deformed against the support in order to close the check valve.

Abstract: The fluid dispenser device is fitted on the neck of a reservoir, and it includes a pump having a metering chamber that is closed by a first needle forming a check valve; a dispenser endpiece fitted on the pump including a second needle, forming a check valve, and a thrust surface to enable the device to be activated by a user pressing thereon; a protective cap for the device; a clamping collar carrying the cap; and a fastener member for fastening the device on the neck of the reservoir, the fastener member including an attachment member for attaching the fastener member around the neck and activatable by sliding the collar relative to the fastener member from a pre-assembly configuration to an assembled configuration, an inner ring for centering the pump on the reservoir and an outer ring retaining member for retaining the dispenser endpiece.