Abstract: Apparatus for retaining concentric parts within one another and enabling limited axial movement therebetween, includes an inner component having a shoulder disposed in an external perimeter thereof and an outer tubular component having a wall and an open end for receiving the inner component and an inner surface for abutting the shoulder and enabling a sliding interface therebetween. A retaining tab is provided and disposed in the wall proximate the open end for depression of a free end toward the wall and a slot formed in the wall beneath the tab enables the free end to be forced therepast for retaining the free end inside the wall for engagement with the shoulder, thus preventing separation of the inner component from the outer component.