the vlier pull pin is due to it's long travel a premium product compared to it's competitors. All of Vlier style hand retractable plungers are offered in both locking and non-locking styles.
The extended plunger length is an advantage in some customer’s applications. Pull ring versions of competitors do not have the possibility of having so much travel. The non-locking style of this plunger is also designed for smaller applications that do not allow for enough room.